Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.107
Filtrar
1.
Nat Commun ; 11(1): 3906, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764563

RESUMO

Enzymatic hydroxylation of unactivated primary carbons is generally associated with the use of molecular oxygen as co-substrate for monooxygenases. However, in anaerobic cholesterol-degrading bacteria such as Sterolibacterium denitrificans the primary carbon of the isoprenoid side chain is oxidised to a carboxylate in the absence of oxygen. Here, we identify an enzymatic reaction sequence comprising two molybdenum-dependent hydroxylases and one ATP-dependent dehydratase that accomplish the hydroxylation of unactivated primary C26 methyl group of cholesterol with water: (i) hydroxylation of C25 to a tertiary alcohol, (ii) ATP-dependent dehydration to an alkene via a phosphorylated intermediate, (iii) hydroxylation of C26 to an allylic alcohol that is subsequently oxidised to the carboxylate. The three-step enzymatic reaction cascade divides the high activation energy barrier of primary C-H bond cleavage into three biologically feasible steps. This finding expands our knowledge of biological C-H activations beyond canonical oxygenase-dependent reactions.


Assuntos
Trifosfato de Adenosina/metabolismo , Betaproteobacteria/metabolismo , Anaerobiose , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Betaproteobacteria/genética , Carbono/química , Colestadienóis/química , Colestadienóis/metabolismo , Colesterol/química , Colesterol/metabolismo , Genes Bacterianos , Hidroliases/genética , Hidroliases/metabolismo , Hidroxilação , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Modelos Biológicos , Oxirredução , Filogenia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Água/metabolismo
2.
PLoS One ; 15(7): e0235642, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32640001

RESUMO

Aspergillus tamarii grows abundantly in naturally composting waste fibers of the textile industry and has a great potential in biomass decomposition. Amongst the key (hemi)cellulose-active enzymes in the secretomes of biomass-degrading fungi are the lytic polysaccharide monooxygenases (LPMOs). By catalyzing oxidative cleavage of glycoside bonds, LPMOs promote the activity of other lignocellulose-degrading enzymes. Here, we analyzed the catalytic potential of two of the seven AA9-type LPMOs that were detected in recently published transcriptome data for A. tamarii, namely AtAA9A and AtAA9B. Analysis of products generated from cellulose revealed that AtAA9A is a C4-oxidizing enzyme, whereas AtAA9B yielded a mixture of C1- and C4-oxidized products. AtAA9A was also active on cellopentaose and cellohexaose. Both enzymes also cleaved the ß-(1→4)-glucan backbone of tamarind xyloglucan, but with different cleavage patterns. AtAA9A cleaved the xyloglucan backbone only next to unsubstituted glucosyl units, whereas AtAA9B yielded product profiles indicating that it can cleave the xyloglucan backbone irrespective of substitutions. Building on these new results and on the expanding catalog of xyloglucan- and oligosaccharide-active AA9 LPMOs, we discuss possible structural properties that could underlie the observed functional differences. The results corroborate evidence that filamentous fungi have evolved AA9 LPMOs with distinct substrate specificities and regioselectivities, which likely have complementary functions during biomass degradation.


Assuntos
Aspergillus/metabolismo , Proteínas Fúngicas/metabolismo , Glucanos/metabolismo , Oxigenases de Função Mista/metabolismo , Xilanos/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , Cobre/química , Cobre/metabolismo , Proteínas Fúngicas/classificação , Proteínas Fúngicas/genética , Glucanos/análise , Glucanos/química , Oxigenases de Função Mista/classificação , Oxigenases de Função Mista/genética , Oxirredução , Filogenia , Polissacarídeos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Especificidade por Substrato , Xilanos/química
3.
Proc Natl Acad Sci U S A ; 117(30): 17820-17831, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32661174

RESUMO

The discovery of atrial secretory granules and the natriuretic peptides stored in them identified the atrium as an endocrine organ. Although neither atrial nor brain natriuretic peptide (ANP, BNP) is amidated, the major membrane protein in atrial granules is peptidylglycine α-amidating monooxygenase (PAM), an enzyme essential for amidated peptide biosynthesis. Mice lacking cardiomyocyte PAM (Pam Myh6-cKO/cKO) are viable, but a gene dosage-dependent drop in atrial ANP and BNP content occurred. Ultrastructural analysis of adult Pam Myh6-cKO/cKO atria revealed a 13-fold drop in the number of secretory granules. When primary cultures of Pam 0-Cre-cKO/cKO atrial myocytes (no Cre recombinase, PAM floxed) were transduced with Cre-GFP lentivirus, PAM protein levels dropped, followed by a decline in ANP precursor (proANP) levels. Expression of exogenous PAM in Pam Myh6-cKO/cKO atrial myocytes produced a dose-dependent rescue of proANP content; strikingly, this response did not require the monooxygenase activity of PAM. Unlike many prohormones, atrial proANP is stored intact. A threefold increase in the basal rate of proANP secretion by Pam Myh6-cKO/cKO myocytes was a major contributor to its reduced levels. While proANP secretion was increased following treatment of control cultures with drugs that block the activation of Golgi-localized Arf proteins and COPI vesicle formation, proANP secretion by Pam Myh6-cKO/cKO myocytes was unaffected. In cells lacking secretory granules, expression of exogenous PAM led to the accumulation of fluorescently tagged proANP in the cis-Golgi region. Our data indicate that COPI vesicle-mediated recycling of PAM from the cis-Golgi to the endoplasmic reticulum plays an essential role in the biogenesis of proANP containing atrial granules.


Assuntos
Amidina-Liases/metabolismo , Grânulos Citoplasmáticos/metabolismo , Átrios do Coração/metabolismo , Oxigenases de Função Mista/metabolismo , Vesículas Secretórias/metabolismo , Amidina-Liases/genética , Animais , Fator Natriurético Atrial/metabolismo , Grânulos Citoplasmáticos/ultraestrutura , Expressão Gênica , Complexo de Golgi/metabolismo , Complexo de Golgi/ultraestrutura , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Camundongos , Camundongos Knockout , Oxigenases de Função Mista/genética , Monócitos/metabolismo , Células Musculares/metabolismo , Vesículas Secretórias/ultraestrutura
4.
Nat Commun ; 11(1): 3671, 2020 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-32699299

RESUMO

Epigenetic reprogramming is a cancer hallmark, but how it unfolds during early neoplastic events and its role in carcinogenesis and cancer progression is not fully understood. Here we show that resetting from primed to naïve human pluripotency results in acquisition of a DNA methylation landscape mirroring the cancer DNA methylome, with gradual hypermethylation of bivalent developmental genes. We identify a dichotomy between bivalent genes that do and do not become hypermethylated, which is also mirrored in cancer. We find that loss of H3K4me3 at bivalent regions is associated with gain of methylation. Additionally, we observe that promoter CpG island hypermethylation is not restricted solely to emerging naïve cells, suggesting that it is a feature of a heterogeneous intermediate population during resetting. These results indicate that transition to naïve pluripotency and oncogenic transformation share common epigenetic trajectories, which implicates reprogramming and the pluripotency network as a central hub in cancer formation.


Assuntos
Transformação Celular Neoplásica/genética , Reprogramação Celular , Metilação de DNA , Epigênese Genética , Neoplasias/genética , Animais , Linhagem Celular , Técnicas de Cocultura , Ilhas de CpG/genética , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Fibroblastos , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Células HEK293 , Histonas/genética , Histonas/metabolismo , Células-Tronco Embrionárias Humanas , Humanos , Camundongos , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Interferente Pequeno/metabolismo
5.
Nat Commun ; 11(1): 2991, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32532989

RESUMO

Biocatalysts that perform C-H hydroxylation exhibit exceptional substrate specificity and site-selectivity, often through the use of high valent oxidants to activate these inert bonds. Rieske oxygenases are examples of enzymes with the ability to perform precise mono- or dioxygenation reactions on a variety of substrates. Understanding the structural features of Rieske oxygenases responsible for control over selectivity is essential to enable the development of this class of enzymes for biocatalytic applications. Decades of research has illuminated the critical features common to Rieske oxygenases, however, structural information for enzymes that functionalize diverse scaffolds is limited. Here, we report the structures of two Rieske monooxygenases involved in the biosynthesis of paralytic shellfish toxins (PSTs), SxtT and GxtA, adding to the short list of structurally characterized Rieske oxygenases. Based on these structures, substrate-bound structures, and mutagenesis experiments, we implicate specific residues in substrate positioning and the divergent reaction selectivity observed in these two enzymes.


Assuntos
Variação Genética , Proteínas com Ferro-Enxofre/genética , Oxigenases de Função Mista/genética , Oxigenases/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação/genética , Biocatálise , Domínio Catalítico , Cianobactérias/enzimologia , Cianobactérias/genética , Hidroxilação , Proteínas com Ferro-Enxofre/química , Proteínas com Ferro-Enxofre/metabolismo , Cinética , Oxigenases de Função Mista/química , Oxigenases de Função Mista/metabolismo , Modelos Moleculares , Oxigenases/química , Oxigenases/metabolismo , Conformação Proteica , Multimerização Proteica , Especificidade por Substrato
6.
Prostate ; 80(12): 977-985, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32542727

RESUMO

BACKGROUND: Recently, resveratrol (Res) has been suggested to suppress the migration and invasion of prostate cancer (PCa). In the present study, we aimed to investigate the effects of Res on genomic DNA methylation, as well as the migration and invasion of PCa cells. METHODS: The suppression by Res of the growth of PCa cells was verified through a cytotoxicity assay. In addition, the effects of Res on 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC), and ten-eleven translocation 1 (TET1) levels were assessed, and the cell migration and invasion were also determined. The expressions of TET1, tissue inhibitor of metalloproteinases (TIMP) 2, TIMP3, MMP2, and MMP9 were detected through Western blot analysis. Afterward, TET1 was silenced using lentiviral short hairpin RNA to examine the effect of TET1 on the Res-triggered inhibition of migration and invasion of PCa cells. RESULTS: Our results showed that Res upregulated the 5hmC and TET1 levels and downregulated the 5mC level. Moreover, Res also inhibited the migration and invasion of PCa cells, promoted the demethylation of TIMP2 and TIMP3 to upregulate their expressions, and suppressed the expressions of MMP2 and MMP9. The silencing of TET1 in the presence of Res showed that Res could exert its effect through TET1. CONCLUSIONS: Our findings indicated that Res inhibited the migration and invasion of PCa cells via the TET1/TIMP2/TIMP3 pathway, which might potentially serve as a target for the treatment of PCa.


Assuntos
Oxigenases de Função Mista/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Resveratrol/farmacologia , Inibidor Tecidual de Metaloproteinase-2/metabolismo , Inibidor Tecidual de Metaloproteinase-3/metabolismo , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Metilação de DNA/efeitos dos fármacos , Células HEK293 , Humanos , Masculino , Oxigenases de Função Mista/biossíntese , Oxigenases de Função Mista/genética , Invasividade Neoplásica , Células PC-3 , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Resveratrol/farmacocinética , Inibidor Tecidual de Metaloproteinase-2/biossíntese , Inibidor Tecidual de Metaloproteinase-2/genética , Inibidor Tecidual de Metaloproteinase-3/biossíntese , Inibidor Tecidual de Metaloproteinase-3/genética , Regulação para Cima
7.
Nat Commun ; 11(1): 2600, 2020 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451409

RESUMO

Light-dependent or light-stimulated catalysis provides a multitude of perspectives for implementation in technological or biomedical applications. Despite substantial progress made in the field of photobiocatalysis, the number of usable light-responsive enzymes is still very limited. Flavoproteins have exceptional potential for photocatalytic applications because the name-giving cofactor intrinsically features light-dependent reactivity, undergoing photoreduction with a variety of organic electron donors. However, in the vast majority of these enzymes, photoreactivity of the enzyme-bound flavin is limited or even suppressed. Here, we present a flavoprotein monooxygenase in which catalytic activity is controllable by blue light illumination. The reaction depends on the presence of nicotinamide nucleotide-type electron donors, which do not support the reaction in the absence of light. Employing various experimental approaches, we demonstrate that catalysis depends on a protein-mediated photoreduction of the flavin cofactor, which proceeds via a radical mechanism and a transient semiquinone intermediate.


Assuntos
Proteínas de Bactérias/metabolismo , Transporte de Elétrons , Flavina-Adenina Dinucleotídeo/metabolismo , Oxigenases de Função Mista/metabolismo , NAD/metabolismo , Pseudomonas aeruginosa/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biocatálise , Cristalografia por Raios X , Flavoproteínas Transferidoras de Elétrons/química , Flavoproteínas Transferidoras de Elétrons/genética , Flavoproteínas Transferidoras de Elétrons/metabolismo , Luz , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Modelos Moleculares , NADP/metabolismo , Oxirredução , Processos Fotoquímicos , Pseudomonas aeruginosa/genética
8.
PLoS One ; 15(5): e0231355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32437389

RESUMO

The overexploitation of medicinal plants is depleting gene pool at an alarming rate. In this scenario inducing the genetic variability through targeted mutations could be beneficial in generating varieties with increased content of active compounds. The present study aimed to develop a reproducible protocol for in vitro multiplication and mutagenesis of Hyoscyamus niger targeting putrescine N-methyltransferase (PMT) and 6ß-hydroxy hyoscyamine (H6H) genes of alkaloid biosynthetic pathway. In vitro raised callus were treated with different concentrations (0.01% - 0.1%) of Ethyl Methane Sulfonate (EMS). Emerging multiple shoots and roots were obtained on the MS media supplemented with cytokinins and auxins. Significant effects on morphological characteristics were observed following exposure to different concentrations of EMS. EMS at a concentration of 0.03% was seen to be effective in enhancing the average shoot and root number from 14.5±0.30 to 22.2 ±0.77 and 7.2±0.12 to 8.8±0.72, respectively. The lethal dose (LD50) dose was calculated at 0.08% EMS. The results depicted that EMS has an intense effect on PMT and H6H gene expression and metabolite accumulation. The transcripts of PMT and H6H were significantly upregulated at 0.03-0.05% EMS compared to control. EMS treated explants showed increased accumulation of scopolamine (0.639 µg/g) and hyoscyamine (0.0344µg/g) compared to untreated.


Assuntos
Metanossulfonato de Etila/toxicidade , Hiosciamina/metabolismo , Hyoscyamus/crescimento & desenvolvimento , Metiltransferases/genética , Oxigenases de Função Mista/genética , Mutagênese , Mutação , Escopolamina/metabolismo , Vias Biossintéticas , Regulação da Expressão Gênica de Plantas , Hyoscyamus/efeitos dos fármacos , Hyoscyamus/genética , Hyoscyamus/metabolismo , Mutagênicos/toxicidade , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/metabolismo
9.
Artigo em Inglês | MEDLINE | ID: mdl-32460213

RESUMO

Datura innoxia Mill., a traditional Chinese herbal medicine, produces tropane alkaloids such as hyoscyamine and scopolamine. Scopolamine has a larger demand than hyoscyamine due to its stronger pharmacological effects and fewer side reactions. It is extracted from solanaceous plants. However, the content of scopolamine is lower than hyoscyamine in D. innoxia. Hyoscyamine 6ß-hydroxylase (H6H, EC1.14.11.11) is the key enzyme which can catalyze hyoscyamine to form scopolamine. In this study, a cDNA encoding H6H was cloned from D. innoxia roots and named Dih6h. The full-length cDNA is 1413 bp in length with a 1044-bp open reading frame encoding 347 amino acids. The deduced protein sequence of D. innoxia H6H (DiH6H) shared high identity with H6Hs from other plants. The DiH6H was heterologously expressed in Escherichia coli and purified via His-tag affinity technique. The recombinant DiH6H showed activity in transforming hyoscyamine to scopolamine. Despite Dih6h mRNA was detected in various tissues, its levels in roots were higher than that in other tissues. Indeed, scopolamine accumulation was low in roots, but it was very high in aerial parts, especially in flowers and seeds. These observations suggest that scopolamine may be synthesized in the roots and subsequently transported to the aerial parts. To further verify in vivo function of DiH6H, the cDNA of DiH6H was overexpressed in D. innoxia hairy roots. As expected, an increase of scopolamine production was observed in the positive transformants. The results provide a potential strategy for increasing scopolamine yield by metabolic engineering of its biosynthetic pathway in D. innoxia.


Assuntos
Datura/enzimologia , Oxigenases de Função Mista/genética , Proteínas de Plantas/genética , Clonagem Molecular , Datura/genética , Plantas Medicinais/enzimologia , Plantas Medicinais/genética
10.
Nat Commun ; 11(1): 1515, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32251291

RESUMO

Hydroxytyrosol is an antioxidant free radical scavenger that is biosynthesized from tyrosine. In metabolic engineering efforts, the use of the mouse tyrosine hydroxylase limits its production. Here, we design an efficient whole-cell catalyst of hydroxytyrosol in Escherichia coli by de-bottlenecking two rate-limiting enzymatic steps. First, we replace the mouse tyrosine hydroxylase by an engineered two-component flavin-dependent monooxygenase HpaBC of E. coli through structure-guided modeling and directed evolution. Next, we elucidate the structure of the Corynebacterium glutamicum VanR regulatory protein complexed with its inducer vanillic acid. By switching its induction specificity from vanillic acid to hydroxytyrosol, VanR is engineered into a hydroxytyrosol biosensor. Then, with this biosensor, we use in vivo-directed evolution to optimize the activity of tyramine oxidase (TYO), the second rate-limiting enzyme in hydroxytyrosol biosynthesis. The final strain reaches a 95% conversion rate of tyrosine. This study demonstrates the effectiveness of sequentially de-bottlenecking rate-limiting steps for whole-cell catalyst development.


Assuntos
Evolução Molecular Direcionada/métodos , Escherichia coli/enzimologia , Depuradores de Radicais Livres/metabolismo , Engenharia Metabólica , Álcool Feniletílico/análogos & derivados , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Técnicas Biossensoriais , Vias Biossintéticas/genética , Corynebacterium glutamicum/enzimologia , Corynebacterium glutamicum/genética , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Estudos de Viabilidade , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Mutagênese Sítio-Dirigida , Mutação , Álcool Feniletílico/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Tirosina/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Ácido Vanílico/metabolismo
11.
Arch Microbiol ; 202(6): 1507-1515, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32222778

RESUMO

Pyocyanin produced by Pseudomonas aeruginosa is a key virulence factor that often causes heavy damages to airway and lung in patients. Conversion of phenazine-1-carboxylic acid to pyocyanin involves an extrametabolic pathway that contains two enzymes encoded, respectively, by phzM and phzS. In this study, with construction of the rpoS-deficient mutant, we first found that although phenazine production increased, pyocyanin produced in the mutant YTΔrpoS was fourfold much higher than that in the wild-type strain YT. To investigate this issue, we constructed phzM-lacZ fusion on a vector and on the chromosome. By quantifying ß-galactosidase activities, we confirmed that expression of the phzM was up-regulated when the rpoS gene was inactivated. However, no changes occurred in the expression of phzS and phzH when the rpoS was knocked out. Taken together, overproduction of the SAM-dependent methyltransferase (PhzM) might contribute to the increased pyocyanin in the absence of RpoS in P. aeruginosa.


Assuntos
Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Metiltransferases/biossíntese , Oxigenases de Função Mista/biossíntese , Pseudomonas aeruginosa/metabolismo , Piocianina/biossíntese , Fator sigma/genética , Humanos , Metiltransferases/genética , Oxigenases de Função Mista/genética , Fenazinas/metabolismo , Pseudomonas aeruginosa/genética , Fatores de Virulência/metabolismo
12.
Ecotoxicol Environ Saf ; 192: 110250, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32028154

RESUMO

A bacterial strain designated Lysinibacillus fusiformis 15-4 was isolated from oil-free soil on the Qinghai-Tibet Plateau, which can grow well utilizing petroleum hydrocarbons as a carbon source at a lower temperature. To deeply characterize the molecular adaptations and metabolic processes of this strain when grown in a petroleum-containing environment, transcriptome analysis was performed. A total of 4664 genes and the expression of 3969 genes were observed in strain 15-4. When the strain was grown in petroleum-containing medium, 2192 genes were significantly regulated, of which 1312 (60%) were upregulated and 880 (40%) were downregulated. This strain degraded and adapted to petroleum via modulation of diverse molecular processes, including improvements in transporter activity, oxidoreductase/dehydrogenase activity, two-component system/signal transduction, transcriptional regulation, fatty acid catabolism, amino acid metabolism, and environmental stress responses. Many strain-specific genes were involved in the oxidation of hydrocarbon compounds, such as several luciferase family alkane monooxygenase genes, flavin-utilizing monooxygenase family genes, and flavoprotein-like family alkanesulfonate monooxygenase genes. Several cold shock protein genes were also induced suggesting adaptation to cold environments and the potential for petroleum degradation at low temperatures. The results obtained in this study may broaden our understanding of molecular adaptation of bacteria to hydrocarbon-containing environments and may provide valuable data for further study of L. fusiformis.


Assuntos
Bacillaceae/genética , Bacillaceae/metabolismo , Petróleo/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Adaptação Fisiológica , Bacillaceae/isolamento & purificação , Biodegradação Ambiental , Proteínas e Peptídeos de Choque Frio/biossíntese , Proteínas e Peptídeos de Choque Frio/genética , Temperatura Baixa , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Hidrocarbonetos/metabolismo , Oxigenases de Função Mista/biossíntese , Oxigenases de Função Mista/genética , Microbiologia do Solo , Tibet
13.
Ann Otol Rhinol Laryngol ; 129(7): 653-656, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32028786

RESUMO

OBJECTIVES: Congenital midline cervical cleft (CMCC) is a rare congenital anterior neck anatomical anomaly. We present the case of two related patients (grandchild and maternal grandmother) who were both born with a congenital midline cervical cleft along with genetic analysis. METHODS: Clinical examination of both patients and surgical excision of the grandchild was performed. Genetic analysis with exome sequencing (ES) was conducted for both patients. RESULTS: Genetic analysis with exome sequencing (ES) revealed apparently novel single nucleotide variants in 66 genes present in both proband and grandmother. Five of these variants are predicted to cause frameshifting in the coding region of the respective genes and truncated proteins (OVGP1, TYW1B, ZAN, SSPO, FOLR3). Two of these genes (TYW1B and SSPO) have homozygous indel mutations in both patients. CONCLUSIONS: To our knowledge, this is the first case of two related patients with a congenital midline cervical cleft. The results of our genetic analysis reveal potential relevance to CMCC development.


Assuntos
Região Branquial/anormalidades , Proteínas de Transporte/genética , Moléculas de Adesão Celular Neuronais/genética , Anormalidades Craniofaciais/genética , Glicoproteínas/genética , Pescoço/anormalidades , Doenças Faríngeas/genética , Região Branquial/cirurgia , Anormalidades Craniofaciais/cirurgia , Feminino , Mutação da Fase de Leitura , Avós , Humanos , Mutação INDEL , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Oxigenases de Função Mista/genética , Pescoço/cirurgia , Doenças Faríngeas/cirurgia , Polimorfismo de Nucleotídeo Único , Sequenciamento Completo do Exoma
14.
Proc Natl Acad Sci U S A ; 117(7): 3621-3626, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32024762

RESUMO

Ten-eleven translocation (TET) family enzymes (TET1, TET2, and TET3) oxidize 5-methylcytosine (5mC) and generate 5-hydroxymethylcytosine (5hmC) marks on the genome. Each TET protein also interacts with specific binding partners and partly plays their role independent of catalytic activity. Although the basic role of TET enzymes is well established now, the molecular mechanism and specific contribution of their catalytic and noncatalytic domains remain elusive. Here, by combining in silico and biochemical screening strategy, we have identified a small molecule compound, C35, as a first-in-class TET inhibitor that specifically blocks their catalytic activities. Using this inhibitor, we explored the enzymatic function of TET proteins during somatic cell reprogramming. Interestingly, we found that C35-mediated TET inactivation increased the efficiency of somatic cell programming without affecting TET complexes. Using high-throughput mRNA sequencing, we found that by targeting 5hmC repressive marks in the promoter regions, C35-mediated TET inhibition activates the transcription of the BMP-SMAD-ID signaling pathway, which may be responsible for promoting somatic cell reprogramming. These results suggest that C35 is an important tool for inducing somatic cell reprogramming, as well as for dissecting the other biological functions of TET enzymatic activities without affecting their other nonenzymatic roles.


Assuntos
Reprogramação Celular , Proteínas de Ligação a DNA/antagonistas & inibidores , Dioxigenases/antagonistas & inibidores , Inibidores Enzimáticos/química , Proteínas Proto-Oncogênicas/antagonistas & inibidores , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Domínio Catalítico , Linhagem Celular , Reprogramação Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Dioxigenases/química , Dioxigenases/genética , Dioxigenases/metabolismo , Humanos , Oxigenases de Função Mista/antagonistas & inibidores , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo
15.
Proc Natl Acad Sci U S A ; 117(8): 4169-4179, 2020 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-32029597

RESUMO

Abscission is the terminal step of cytokinesis leading to the physical separation of the daughter cells. In response to the abnormal presence of lagging chromatin between dividing cells, an evolutionarily conserved abscission/NoCut checkpoint delays abscission and prevents formation of binucleated cells by stabilizing the cytokinetic intercellular bridge (ICB). How this bridge is stably maintained for hours while the checkpoint is activated is poorly understood and has been proposed to rely on F-actin in the bridge region. Here, we show that actin polymerization is indeed essential for stabilizing the ICB when lagging chromatin is present, but not in normal dividing cells. Mechanistically, we found that a cytosolic pool of human methionine sulfoxide reductase B2 (MsrB2) is strongly recruited at the midbody in response to the presence of lagging chromatin and functions within the ICB to promote actin polymerization there. Consistently, in MsrB2-depleted cells, F-actin levels are decreased in ICBs, and dividing cells with lagging chromatin become binucleated as a consequence of unstable bridges. We further demonstrate that MsrB2 selectively reduces oxidized actin monomers and thereby counteracts MICAL1, an enzyme known to depolymerize actin filaments by direct oxidation. Finally, MsrB2 colocalizes and genetically interacts with the checkpoint components Aurora B and ANCHR, and the abscission delay upon checkpoint activation by nuclear pore defects also depends on MsrB2. Altogether, this work reveals that actin reduction by MsrB2 is a key component of the abscission checkpoint that favors F-actin polymerization and limits tetraploidy, a starting point for tumorigenesis.


Assuntos
Actinas/metabolismo , Cromatina/metabolismo , Citocinese/fisiologia , Proteínas de Drosophila/metabolismo , Metionina Sulfóxido Redutases/metabolismo , Proteínas dos Microfilamentos/metabolismo , Mitose/fisiologia , Animais , Linhagem Celular , Drosophila , Proteínas de Drosophila/genética , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Células HeLa , Humanos , Metionina Sulfóxido Redutases/genética , Proteínas dos Microfilamentos/genética , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Oxirredução
16.
Oncol Rep ; 43(3): 827-838, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32020216

RESUMO

Restoration of normal DNA promoter methylation and expression states of cancer­related genes may be an option for the prevention as well as the treatment of several types of cancer. Constitutional promoter methylation of BRCA1 DNA repair associated (BRCA1) gene is linked with a high risk of developing breast and ovarian cancer. Furthermore, hypomethylation of the proto­oncogene Î³ synuclein (SNCG) is associated with the metastasis of breast and ovarian cancer and reduced disease­free survival (DFS). In the present study, we evaluated the potential of curcumin to re­express hypermethylated BRCA1 and to suppress hypomethylated SNCG in triple­negative breast cancer (TNBC) cell line HCC­38, the estrogen receptor­negative/progesterone receptor­negative (ER­/PR­) cell line UACC­3199, and the ER+/PR+ cell line T47D. The cells were treated with 5 and 10 µM curcumin for 6 days and with 5­aza­2'­deoxycytidine (5'­aza­CdR) for 48 h. Methylation­specific PCR and bisulfite pyrosequencing assays were used to assess DNA promoter methylation while gene expression levels were analyzed using quantitative real­time PCR and immunoblotting. We found that curcumin treatment restored BRCA1 gene expression by reducing the DNA promoter methylation level in HCC­38 and UACC­3199 cells and that it suppressed the expression of SNCG by inducing DNA promoter methylation in T47D cells. Notably, 5'­aza­CdR restored BRCA1 gene expression only in UACC­3199, and not in HCC­38 cells. Curcumin­induced hypomethylation of the BRCA1 promoter appears to be realized through the upregulation of the ten­eleven translocation 1 (TET1) gene, whereas curcumin­induced hypermethylation of SNCG may be realized through the upregulation of the DNA methyltransferase 3 (DNMT3) and the downregulation of TET1. Notably, miR­29b was found to be reversely expressed compared to TET1 in curcumin­ and 5'­aza­CdR­treated cells, suggesting its involvement in the regulation of TET1. Overall, our results indicate that curcumin has an intrinsic dual function on DNA promoter methylation. We believe that curcumin may be considered a promising therapeutic option for treating TNBC patients in addition to preventing breast and ovarian cancer, particularly in cancer­free females harboring methylated BRCA1.


Assuntos
Proteína BRCA1/genética , Curcumina/farmacologia , DNA (Citosina-5-)-Metiltransferases/genética , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , gama-Sinucleína/genética , Azacitidina/farmacologia , Linhagem Celular Tumoral , Metilação de DNA/efeitos dos fármacos , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , MicroRNAs/genética , Oxigenases de Função Mista/genética , Regiões Promotoras Genéticas/efeitos dos fármacos , Proteínas Proto-Oncogênicas/genética , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/patologia
17.
Gene ; 731: 144341, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-31935502

RESUMO

Hypoxia is one of the major challenges in aquaculture industry. Breeding of fish tolerant to hypoxia is an important task in genetic improvement of aquaculture species. The Asian seabass, Lates calcarifer, is an important foodfish species. We identified and characterized the hypoxia-inducible factor inhibitor (HIF1αn) gene in the Asian seabass. The full-length cDNA sequence of the HIF1αn was 3425 bp, with an ORF of 1065 bp, encoding 354 amino acids. The genomic sequence of the gene was 8667 bp in length, and contained eight exons and seven introns. Phylogenetic analysis of the gene in fish and tetrapods revealed that the HIF1αn in the Asian seabass was closely related to that of tilapia (Oreochromis niloticus). The HIF1αn was highly up-regulated in the gill, spleen and heart after 3.5-hours hypoxia treatment. We identified three SNPs in the third and fourth introns of the HIF1αn gene. The SNP (i.e. SNP 9332241 (C/T)) in the fourth intron was significantly (P < 0.01) associated with hypoxia tolerance. This SNP might be useful in selecting Asian seabass for improved tolerance to hypoxia. Our data also provide useful information for further detailed analysis of the function of the HIF1αn gene in hypoxia tolerance.


Assuntos
Adaptação Biológica/genética , Bass/genética , Hipóxia/genética , Oxigenases de Função Mista/genética , Animais , Bass/classificação , Bass/metabolismo , Clonagem Molecular , Feminino , Estudos de Associação Genética/veterinária , Masculino , Oxigenases de Função Mista/metabolismo , Perciformes/classificação , Perciformes/genética , Filogenia , Polimorfismo de Nucleotídeo Único , Proteínas Repressoras/genética , Homologia de Sequência , Proteínas de Peixe-Zebra/genética
18.
Appl Microbiol Biotechnol ; 104(5): 2255-2269, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31956944

RESUMO

1,4-Dioxane, a co-contaminant at many chlorinated solvent sites, is a problematic groundwater pollutant because of risks to human health and characteristics which make remediation challenging. In situ 1,4-dioxane bioremediation has recently been shown to be an effective remediation strategy. However, the presence/abundance of 1,4-dioxane degrading species across different environmental samples is generally unknown. Here, the objectives were to identify which 1,4-dioxane degrading functional genes are present and which genera may be using 1,4-dioxane and/or metabolites to support growth across different microbial communities. For this, laboratory sample microcosms and abiotic control microcosms (containing media) were inoculated with four uncontaminated soils and sediments from two contaminated sites. Live control microcosms were treated in the same manner, except 1,4-dioxane was not added. 1,4-Dioxane decreased in live microcosms with all six inocula, but not in the abiotic controls, suggesting biodegradation occurred. A comparison of live sample microcosms and live controls (no 1,4-dioxane) indicated nineteen genera were enriched following exposure to 1,4-dioxane, suggesting a growth benefit for 1,4-dioxane biodegradation. The three most enriched were Mycobacterium, Nocardioides, and Kribbella (classifying as Actinomycetales). There was also a higher level of enrichment for Arthrobacter, Nocardia, and Gordonia (all three classifying as Actinomycetales) in one soil, Hyphomicrobium (Rhizobiales) in another soil, Clavibacter (Actinomycetales) and Bartonella (Rhizobiales) in another soil, and Chelativorans (Rhizobiales) in another soil. Although Arthrobacter, Mycobacterium, and Nocardia have previously been linked to 1,4-dioxane degradation, Nocardioides, Gordonia, and Kribbella are potentially novel degraders. The analysis of the functional genes associated with 1,4-dioxane demonstrated three genes were present at higher relative abundance values, including Rhodococcus sp. RR1 prmA, Rhodococcus jostii RHA1 prmA, and Burkholderia cepacia G4 tomA3. Overall, this study provides novel insights into the identity of the multiple genera and functional genes associated with aerobic degradation of 1,4-dioxane in mixed communities.


Assuntos
Actinomycetales/metabolismo , Proteínas de Bactérias/genética , Dioxanos/metabolismo , Oxigenases de Função Mista/genética , Poluentes Químicos da Água/metabolismo , Actinomycetales/classificação , Actinomycetales/genética , Actinomycetales/crescimento & desenvolvimento , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Biodegradação Ambiental , Filogenia , Microbiologia do Solo
19.
Nat Commun ; 11(1): 186, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924762

RESUMO

Sodium (Na+) toxicity is one of the major damages imposed on crops by saline-alkaline stress. Here we show that natural maize inbred lines display substantial variations in shoot Na+ contents and saline-alkaline (NaHCO3) tolerance, and reveal that ZmNSA1 (Na+ Content under Saline-Alkaline Condition) confers shoot Na+ variations under NaHCO3 condition by a genome-wide association study. Lacking of ZmNSA1 promotes shoot Na+ homeostasis by increasing root Na+ efflux. A naturally occurred 4-bp deletion decreases the translation efficiency of ZmNSA1 mRNA, thus promotes Na+ homeostasis. We further show that, under saline-alkaline condition, Ca2+ binds to the EF-hand domain of ZmNSA1 then triggers its degradation via 26S proteasome, which in turn increases the transcripts levels of PM-H+-ATPases (MHA2 and MHA4), and consequently enhances SOS1 Na+/H+ antiporter-mediated root Na+ efflux. Our studies reveal the mechanism of Ca2+-triggered saline-alkaline tolerance and provide an important gene target for breeding saline-alkaline tolerant maize varieties.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Tolerância ao Sal/fisiologia , Sódio/metabolismo , Zea mays/fisiologia , Proteínas de Ligação ao Cálcio/genética , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Homeostase , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Tolerância ao Sal/genética , Cloreto de Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Zea mays/genética
20.
FASEB J ; 34(1): 525-539, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914679

RESUMO

Whereas much is known about the genes regulated by ΔNp63α in keratinocytes, how ΔNp63α is regulated is less clear. During studies with the hydroxylase, factor inhibiting hypoxia-inducible factor 1 (FIH-1), we observed increases in epidermal ΔNp63α expression along with proliferative capacity in a conditional FIH-1 transgenic mouse. Conversely, loss of FIH-1 in vivo and in vitro attenuated ΔNp63α expression. To elucidate the FIH-1/p63 relationship, BioID proteomics assays identified FIH-1 binding partners that had the potential to regulate p63 expression. FIH-1 interacts with two previously unknown partners, Plectin1 and signal transducer and activator of transcription 1 (STAT1) leading to the regulation of ΔNp63α expression. Two known interactors of FIH-1, apoptosis-stimulating of P53 protein 2 (ASPP2) and histone deacetylase 1 (HDAC1), were also identified. Knockdown of ASPP2 upregulated ΔNp63α and reversed the decrease in ΔNp63α by FIH-1 depletion. Additionally, FIH-1 regulates growth arrest and DNA damage-45 alpha (GADD45α), a negative regulator of ΔNp63α by interacting with HDAC1. GADD45α knockdown rescued reduction in ΔNp63α by FIH-1 depletion. Collectively, our data reveal that FIH-1 positively regulates ΔNp63α in keratinocytes via variety of signaling partners: (a) Plectin1/STAT1, (b) ASPP2, and (c) HDAC1/GADD45α signaling pathways.


Assuntos
Proteínas de Transporte/metabolismo , Proliferação de Células , Células Epiteliais/citologia , Queratinócitos/citologia , Proteínas de Membrana/metabolismo , Oxigenases de Função Mista/metabolismo , Proteoma/metabolismo , Proteínas Repressoras/metabolismo , Animais , Células Cultivadas , Células Epiteliais/metabolismo , Humanos , Queratinócitos/metabolismo , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Oxigenases de Função Mista/genética , Proteoma/análise , Proteínas Repressoras/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA