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1.
Genes Dev ; 33(19-20): 1381-1396, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31488579

RESUMO

Short telomere syndromes manifest as familial idiopathic pulmonary fibrosis; they are the most common premature aging disorders. We used genome-wide linkage to identify heterozygous loss of function of ZCCHC8, a zinc-knuckle containing protein, as a cause of autosomal dominant pulmonary fibrosis. ZCCHC8 associated with TR and was required for telomerase function. In ZCCHC8 knockout cells and in mutation carriers, genomically extended telomerase RNA (TR) accumulated at the expense of mature TR, consistent with a role for ZCCHC8 in mediating TR 3' end targeting to the nuclear RNA exosome. We generated Zcchc8-null mice and found that heterozygotes, similar to human mutation carriers, had TR insufficiency but an otherwise preserved transcriptome. In contrast, Zcchc8-/- mice developed progressive and fatal neurodevelopmental pathology with features of a ciliopathy. The Zcchc8-/- brain transcriptome was highly dysregulated, showing accumulation and 3' end misprocessing of other low-abundance RNAs, including those encoding cilia components as well as the intronless replication-dependent histones. Our data identify a novel cause of human short telomere syndromes-familial pulmonary fibrosis and uncover nuclear exosome targeting as an essential 3' end maturation mechanism that vertebrate TR shares with replication-dependent histones.


Assuntos
Proteínas de Transporte/genética , Fibrose Pulmonar Idiopática/genética , Mutação com Perda de Função , Proteínas Nucleares/genética , RNA/metabolismo , Telomerase/metabolismo , Animais , Encéfalo/enzimologia , Encéfalo/fisiopatologia , Linhagem Celular , Cílios/genética , Feminino , Ligação Genética , Células HCT116 , Humanos , Fibrose Pulmonar Idiopática/enzimologia , Fibrose Pulmonar Idiopática/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Transtornos do Neurodesenvolvimento/genética , Linhagem , Processamento Pós-Transcricional do RNA/genética , Encurtamento do Telômero/genética
2.
Int Heart J ; 60(5): 1113-1122, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31484864

RESUMO

Occurring in about 1% of all live births, congenital heart defects (CHDs) represent the most frequent type of developmental abnormality and account for remarkably increased infant morbidity and mortality. Aggregating studies demonstrate that genetic components have a key role in the occurrence of CHDs. Nevertheless, due to pronounced genetic heterogeneity, the genetic causes of CHDs remain unclear in most patients. In this research, 114 unrelated patients affected with CHDs and 218 unrelated individuals without CHDs served as controls were recruited. The coding regions and splicing donors/acceptors of the ISL1 gene, which codes for a transcription factor required for proper cardiovascular development, were screened for mutations by sequencing in all study participants. The functional characteristics of an identified ISL1 mutation were delineated with a dual-luciferase reporter assay system. As a result, a new heterozygous ISL1 mutation, NM_002202.2: c.225C>G; p. (Tyr75*), was discovered in an index patient with double outlet right ventricle and ventricular septal defect. Analysis of the proband's family unveiled that the mutation co-segregated with the CHD phenotype. The nonsense mutation was absent in the 436 control chromosomes. Biological analysis showed that the mutant ISL1 protein had no transcriptional activity. Furthermore, the mutation nullified the synergistic activation between ISL1 and TBX20, another CHD-associated transcription factor. This research for the first time links an ISL1 loss-of-function mutation to double outlet right ventricle in humans, which adds insight to the molecular pathogenesis underpinning CHDs, suggesting potential implications for timely personalized management of CHD patients.


Assuntos
Dupla Via de Saída do Ventrículo Direito/genética , Genes Reporter/genética , Predisposição Genética para Doença/epidemiologia , Proteínas com Homeodomínio LIM/genética , Mutação com Perda de Função/genética , Fatores de Transcrição/genética , Estudos de Casos e Controles , Causalidade , Pré-Escolar , China/epidemiologia , Dupla Via de Saída do Ventrículo Direito/diagnóstico por imagem , Feminino , Cardiopatias Congênitas/diagnóstico por imagem , Cardiopatias Congênitas/epidemiologia , Cardiopatias Congênitas/genética , Heterozigoto , Hospitais Universitários , Humanos , Incidência , Lactente , Masculino , Mutação , Linhagem , Prognóstico , Estudos Retrospectivos , Medição de Risco
3.
Genet Sel Evol ; 51(1): 36, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31382878

RESUMO

BACKGROUND: Recessive loss-of-function (LOF) alleles at genes which are essential for life, can result in early embryonic mortality. Cattle producers can use the LOF carrier status of individual animals to make selection and mate allocation decisions. METHODS: Two beef cattle breeding strategies i.e. (1) selection against LOF carriers as parents and (2) simultaneous selection and mate allocation to avoid the occurrence of homozygous offspring in three scenarios, which differed in number and frequency of LOF alleles were evaluated using the mate selection program, MateSel. Scenarios included (a) seven loci with high-frequency LOF alleles, (b) 76 loci with low-frequency LOF alleles, and (c) 50 loci with random high- and low-frequency LOF alleles. In addition, any savings resulting from the information obtained by varying the percentage (0-100%) of the herd genotyped, together with segregation analysis to cover ungenotyped animals, were calculated to determine (1) which percentage optimized net profit for a fixed cost of genotyping ($30/test), and (2) the breakeven cost for genotyping. RESULTS: With full knowledge of the LOF alleles carried by selection candidates, the most profitable breeding strategy was always simultaneous selection and mate allocation to avoid homozygous affected offspring (aa) as compared to indiscriminate selection against carrier parents (Aa). The breakeven value of genotyping depended on the number of loci modeled, the LOF allele frequencies, and the mating/selection strategies used. Genotyping was most valuable when it was used to avoid otherwise high levels of embryonic mortalities. As the number of essential loci with LOF alleles increased, especially when some were present at relatively high minor allele frequencies, embryonic losses increased, and profit was maximized by genotyping 10 to 20% of a herd and using that information to reduce these losses. CONCLUSIONS: Genotyping 100% of the herd was never the most profitable outcome in any scenario; however, genotyping some proportion of the herd, together with segregation analysis to cover ungenotyped animals, maximized overall profit in scenarios with large numbers of loci with LOF alleles. As more LOF alleles are identified, such a mate selection software will likely be required to optimally select and allocate matings to balance the rate of genetic gain, embryonic losses, and inbreeding.


Assuntos
Cruzamento , Bovinos/genética , Genes Recessivos , Software , Alelos , Animais , Feminino , Fertilidade , Técnicas de Genotipagem/veterinária , Mutação com Perda de Função , Masculino , Seleção Genética
4.
Nat Commun ; 10(1): 3090, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300647

RESUMO

The role of brain somatic mutations in Alzheimer's disease (AD) is not well understood. Here, we perform deep whole-exome sequencing (average read depth 584×) in 111 postmortem hippocampal formation and matched blood samples from 52 patients with AD and 11 individuals not affected by AD. The number of somatic single nucleotide variations (SNVs) in AD brain specimens increases significantly with aging, and the rate of mutation accumulation in the brain is 4.8-fold slower than that in AD blood. The putatively pathogenic brain somatic mutations identified in 26.9% (14 of 52) of AD individuals are enriched in PI3K-AKT, MAPK, and AMPK pathway genes known to contribute to hyperphosphorylation of tau. We show that a pathogenic brain somatic mutation in PIN1 leads to a loss-of-function mutation. In vitro mimicking of haploinsufficiency of PIN1 aberrantly increases tau phosphorylation and aggregation. This study provides new insights into the genetic architecture underlying the pathogenesis of AD.


Assuntos
Doença de Alzheimer/genética , Peptidilprolil Isomerase de Interação com NIMA/genética , Agregação Patológica de Proteínas/genética , Proteínas tau/metabolismo , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/genética , Doença de Alzheimer/patologia , Animais , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Haploinsuficiência , Hipocampo/citologia , Hipocampo/patologia , Humanos , Mutação com Perda de Função , Masculino , Camundongos , Pessoa de Meia-Idade , Taxa de Mutação , Peptidilprolil Isomerase de Interação com NIMA/metabolismo , Neurônios , Fosforilação/genética , Polimorfismo de Nucleotídeo Único , Agregação Patológica de Proteínas/patologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sequenciamento Completo do Exoma
5.
Nat Commun ; 10(1): 3094, 2019 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-31300657

RESUMO

AMPA receptors (AMPARs) are tetrameric ligand-gated channels made up of combinations of GluA1-4 subunits encoded by GRIA1-4 genes. GluA2 has an especially important role because, following post-transcriptional editing at the Q607 site, it renders heteromultimeric AMPARs Ca2+-impermeable, with a linear relationship between current and trans-membrane voltage. Here, we report heterozygous de novo GRIA2 mutations in 28 unrelated patients with intellectual disability (ID) and neurodevelopmental abnormalities including autism spectrum disorder (ASD), Rett syndrome-like features, and seizures or developmental epileptic encephalopathy (DEE). In functional expression studies, mutations lead to a decrease in agonist-evoked current mediated by mutant subunits compared to wild-type channels. When GluA2 subunits are co-expressed with GluA1, most GRIA2 mutations cause a decreased current amplitude and some also affect voltage rectification. Our results show that de-novo variants in GRIA2 can cause neurodevelopmental disorders, complementing evidence that other genetic causes of ID, ASD and DEE also disrupt glutamatergic synaptic transmission.


Assuntos
Deficiência Intelectual/genética , Transtornos do Neurodesenvolvimento/genética , Receptores de AMPA/genética , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Heterozigoto , Humanos , Lactente , Mutação com Perda de Função , Imagem por Ressonância Magnética , Masculino , Transtornos do Neurodesenvolvimento/diagnóstico por imagem , Adulto Jovem
6.
Nat Commun ; 10(1): 2966, 2019 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273213

RESUMO

Mutations in genes encoding components of BAF (BRG1/BRM-associated factor) chromatin remodeling complexes cause neurodevelopmental disorders and tumors. The mechanisms leading to the development of these two disease entities alone or in combination remain unclear. We generated mice with a heterozygous nervous system-specific partial loss-of-function mutation in a BAF core component gene, Smarcb1. These Smarcb1 mutant mice show various brain midline abnormalities that are also found in individuals with Coffin-Siris syndrome (CSS) caused by SMARCB1, SMARCE1, and ARID1B mutations and in SMARCB1-related intellectual disability (ID) with choroid plexus hyperplasia (CPH). Analyses of the Smarcb1 mutant animals indicate that one prominent midline abnormality, corpus callosum agenesis, is due to midline glia aberrations. Our results establish a novel role of Smarcb1 in the development of the brain midline and have important clinical implications for BAF complex-related ID/neurodevelopmental disorders.


Assuntos
Anormalidades Múltiplas/genética , Agenesia do Corpo Caloso/genética , Corpo Caloso/crescimento & desenvolvimento , Face/anormalidades , Deformidades Congênitas da Mão/genética , Deficiência Intelectual/genética , Micrognatismo/genética , Pescoço/anormalidades , Proteína SMARCB1/genética , Anormalidades Múltiplas/diagnóstico por imagem , Agenesia do Corpo Caloso/diagnóstico por imagem , Agenesia do Corpo Caloso/patologia , Alelos , Animais , Criança , Pré-Escolar , Corpo Caloso/citologia , Corpo Caloso/diagnóstico por imagem , Modelos Animais de Doenças , Embrião de Mamíferos , Face/diagnóstico por imagem , Feminino , Deformidades Congênitas da Mão/diagnóstico por imagem , Humanos , Lactente , Deficiência Intelectual/diagnóstico por imagem , Mutação com Perda de Função , Imagem por Ressonância Magnética , Masculino , Camundongos , Camundongos Transgênicos , Micrognatismo/diagnóstico por imagem , Pescoço/diagnóstico por imagem , Neuroglia/patologia , Cultura Primária de Células
7.
Cancer Sci ; 110(10): 3340-3349, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31342590

RESUMO

Aberrant activation of the MET/hepatocyte growth factor (HGF) receptor participates in the malignant behavior of cancer cells, such as invasion-metastasis and resistance to molecular targeted drugs. Many mutations in the MET extracellular region have been reported, but their significance is largely unknown. Here, we report the dysregulation of mutant MET originally found in a lung cancer patient with Val370 to Asp370 (V370D) replacement located in the extracellular SEMA domain. MET-knockout cells were prepared and reconstituted with WT-MET or V370D-MET. HGF stimulation induced MET dimerization and biological responses in cells reconstituted with WT-MET, but HGF did not induce MET dimerization and failed to induce biological responses in V370D-MET cells. The V370D mutation abrogated HGF-dependent drug resistance of lung cancer cells to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI). Compared with WT-MET cells, V370D-MET cells showed different activation patterns in receptor tyrosine kinases upon exposure to survival/growth-stressed conditions. Surface plasmon resonance analysis indicated that affinity between the extracellular region of V370D-MET and HGF was reduced compared with that for WT-MET. Further analysis of the association between V370D-MET and the separate domains of HGF indicated that the SP domain of HGF was unchanged, but its association with the NK4 domain of HGF was mostly lost in V370D-MET. These results indicate that the V370D mutation in the MET receptor impairs the functional association with HGF and is therefore a loss-of-function mutation. This mutation may change the dependence of cancer cell growth/survival on signaling molecules, which may promote cancer cell characteristics under certain conditions.


Assuntos
Fator de Crescimento de Hepatócito/metabolismo , Neoplasias Pulmonares/genética , Mutação de Sentido Incorreto , Proteínas Proto-Oncogênicas c-met/química , Proteínas Proto-Oncogênicas c-met/genética , Animais , Células CHO , Linhagem Celular Tumoral , Cricetulus , Resistencia a Medicamentos Antineoplásicos , Técnicas de Inativação de Genes , Humanos , Mutação com Perda de Função , Domínios Proteicos , Inibidores de Proteínas Quinases/farmacologia , Multimerização Proteica , Proteínas Proto-Oncogênicas c-met/metabolismo , Ativação Transcricional
9.
Nat Commun ; 10(1): 2761, 2019 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-31235698

RESUMO

Cerebral cavernous malformation (CCM) is a neurovascular familial or sporadic disease that is characterised by capillary-venous cavernomas, and is due to loss-of-function mutations to any one of three CCM genes. Familial CCM follows a two-hit mechanism similar to that of tumour suppressor genes, while in sporadic cavernomas only a small fraction of endothelial cells shows mutated CCM genes. We reported that in mouse models and in human patients, endothelial cells lining the lesions have different features from the surrounding endothelium, as they express mesenchymal/stem-cell markers. Here we show that cavernomas originate from clonal expansion of few Ccm3-null endothelial cells that express mesenchymal/stem-cell markers. These cells then attract surrounding wild-type endothelial cells, inducing them to express mesenchymal/stem-cell markers and to contribute to cavernoma growth. These characteristics of Ccm3-null cells are reminiscent of the tumour-initiating cells that are responsible for tumour growth. Our data support the concept that CCM has benign tumour characteristics.


Assuntos
Proteínas Reguladoras de Apoptose/genética , Neoplasias do Sistema Nervoso Central/patologia , Células Endoteliais/patologia , Hemangioma Cavernoso do Sistema Nervoso Central/patologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Proteínas Proto-Oncogênicas/genética , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Biomarcadores/metabolismo , Encéfalo/irrigação sanguínea , Encéfalo/citologia , Encéfalo/patologia , Diferenciação Celular/genética , Linhagem Celular , Neoplasias do Sistema Nervoso Central/genética , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Endotélio Vascular/citologia , Endotélio Vascular/patologia , Feminino , Técnicas de Inativação de Genes , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Mutação com Perda de Função , Proteínas de Membrana/metabolismo , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas/metabolismo
10.
Nat Commun ; 10(1): 2659, 2019 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-31201323

RESUMO

In contrast to the plasma membrane, the vacuole membrane has not yet been associated with electrical excitation of plants. Here, we show that mesophyll vacuoles from Arabidopsis sense and control the membrane potential essentially via the K+-permeable TPC1 and TPK channels. Electrical stimuli elicit transient depolarization of the vacuole membrane that can last for seconds. Electrical excitability is suppressed by increased vacuolar Ca2+ levels. In comparison to wild type, vacuoles from the fou2 mutant, harboring TPC1 channels insensitive to luminal Ca2+, can be excited fully by even weak electrical stimuli. The TPC1-loss-of-function mutant tpc1-2 does not respond to electrical stimulation at all, and the loss of TPK1/TPK3-mediated K+ transport affects the duration of TPC1-dependent membrane depolarization. In combination with mathematical modeling, these results show that the vacuolar K+-conducting TPC1 and TPK1/TPK3 channels act in concert to provide for Ca2+- and voltage-induced electrical excitability to the central organelle of plant cells.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Canais de Cálcio/metabolismo , Potenciais da Membrana/fisiologia , Vacúolos/fisiologia , Proteínas de Arabidopsis/genética , Canais de Cálcio/genética , Sinalização do Cálcio/fisiologia , Membranas Intracelulares/fisiologia , Mutação com Perda de Função , Células do Mesofilo/citologia , Células do Mesofilo/fisiologia , Plantas Geneticamente Modificadas , Potássio/metabolismo , Canais de Potássio/metabolismo , Canais de Potássio de Domínios Poros em Tandem/metabolismo
11.
PLoS Genet ; 15(5): e1008120, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31116744

RESUMO

N6-Methyladenosine (m6A) RNA methylation plays important roles during development in different species. However, knowledge of m6A RNA methylation in monocots remains limited. In this study, we reported that OsFIP and OsMTA2 are the components of m6A RNA methyltransferase complex in rice and uncovered a previously unknown function of m6A RNA methylation in regulation of plant sporogenesis. Importantly, OsFIP is essential for rice male gametogenesis. Knocking out of OsFIP results in early degeneration of microspores at the vacuolated pollen stage and simultaneously causes abnormal meiosis in prophase I. We further analyzed the profile of rice m6A modification during sporogenesis in both WT and OsFIP loss-of-function plants, and identified a rice panicle specific m6A modification motif "UGWAMH". Interestingly, we found that OsFIP directly mediates the m6A methylation of a set of threonine protease and NTPase mRNAs and is essential for their expression and/or splicing, which in turn regulates the progress of sporogenesis. Our findings revealed for the first time that OsFIP plays an indispensable role in plant early sporogenesis. This study also provides evidence for the different functions of the m6A RNA methyltransferase complex between rice and Arabidopsis.


Assuntos
Gametogênese Vegetal , Regulação da Expressão Gênica de Plantas , Metiltransferases/genética , Oryza/genética , Proteínas de Plantas/genética , Subunidades Proteicas/genética , Adenosina/análogos & derivados , Motivos de Aminoácidos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Mutação com Perda de Função , Prófase Meiótica I , Metilação , Metiltransferases/metabolismo , Nucleosídeo-Trifosfatase/genética , Nucleosídeo-Trifosfatase/metabolismo , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Pólen/genética , Pólen/crescimento & desenvolvimento , Pólen/metabolismo , Subunidades Proteicas/metabolismo , RNA de Plantas , Especificidade da Espécie
12.
Nat Commun ; 10(1): 2213, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31101826

RESUMO

Spiradenoma and cylindroma are distinctive skin adnexal tumors with sweat gland differentiation and potential for malignant transformation and aggressive behaviour. We present the genomic analysis of 75 samples from 57 representative patients including 15 cylindromas, 17 spiradenomas, 2 cylindroma-spiradenoma hybrid tumors, and 24 low- and high-grade spiradenocarcinoma cases, together with morphologically benign precursor regions of these cancers. We reveal somatic or germline alterations of the CYLD gene in 15/15 cylindromas and 5/17 spiradenomas, yet only 2/24 spiradenocarcinomas. Notably, we find a recurrent missense mutation in the kinase domain of the ALPK1 gene in spiradenomas and spiradenocarcinomas, which is mutually exclusive from mutation of CYLD and can activate the NF-κB pathway in reporter assays. In addition, we show that high-grade spiradenocarcinomas carry loss-of-function TP53 mutations, while cylindromas may have disruptive mutations in DNMT3A. Thus, we reveal the genomic landscape of adnexal tumors and therapeutic targets.


Assuntos
Carcinoma Adenoide Cístico/genética , Enzima Desubiquitinante CYLD/genética , Proteínas Quinases/genética , Neoplasias das Glândulas Sudoríparas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Adenoide Cístico/patologia , Estudos de Coortes , DNA (Citosina-5-)-Metiltransferases/genética , Análise Mutacional de DNA , Feminino , Humanos , Mutação com Perda de Função , Masculino , Pessoa de Meia-Idade , Mutação de Sentido Incorreto , Domínios Proteicos/genética , Neoplasias das Glândulas Sudoríparas/patologia , Glândulas Sudoríparas/patologia , Proteína Supressora de Tumor p53/genética , Sequenciamento Completo do Exoma
13.
BMC Med Genet ; 20(1): 71, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053111

RESUMO

BACKGROUND: Nail-patella syndrome (NPS) is an autosomal dominant developmental disorder most commonly characterized by dyplasia of nail or patella, the radial head or the humeral head hypoplasia, and, frequently ocular abnormalities and renal disease. It is caused by heterozygous loss-of-function mutations in the LMX1B gene, which encodes LIM homeodomain transcription factor and is essential for regulating the dorsal limb fate. METHODS: A five generation pedigree was recruited. Genomic DNA was extracted from the peripheral blood samples. Mutation detection was performed by Sanger sequencing the LMX1B gene. In silico functional annotation of the variant was performed using the in silico predictors SIFT, PolyPhen-2 and Mutation Taster. RESULTS: A novel heterozygous small deletion within exon 4 of LMX1B, c.712_714delTTC, was identified in a rare five-generation NPS pedigree. The mutation resulted in a deletion of the conserved amino acid phenylalanine at codon 238 (p.Phe238del), which located in the homeodomain of LMX1B may abolish DNA binding with the molecule. Conformational prediction showed that the variation could transform the helical structure comprising p.Phe234, p.Lys235, p.Ala236, and p.Ser237. CONCLUSION: We identified a novel NPS-causing LMX1B mutation and expanded the spectrum of mutations in the LMX1B gene. The c.712_714delTTC mutation may affect the quaternary structure of LMX1B, which is essential for the specification of dorsal limb fate at both zeugopodal and autopodal levels, leading to typical NPS.


Assuntos
Deleção de Genes , Proteínas com Homeodomínio LIM/genética , Síndrome da Unha-Patela/genética , Fatores de Transcrição/genética , China , Códon , Éxons , Feminino , Heterozigoto , Humanos , Mutação com Perda de Função , Masculino , Linhagem
14.
J Anim Sci ; 97(8): 3199-3212, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31115451

RESUMO

This study assessed cellular characteristics of longissimus lumborum (LL) and semitendinosus (ST) muscles in steers genetically selected for low (Low) or high (High) muscling using live muscle scoring, and High steers with 1 copy of the loss-of-function 821 del11 MSTN allele (HighHet). We hypothesized High and HighHet have altered muscle cellular characteristics and mechanisms influencing muscling compared with Low steers. Angus steers 25 mo old comprising 14 High, 19 Low, and 11 HighHet were backgrounded to 20 mo of age, grain finished for 150 d, and then slaughtered. Body and carcass weights did not differ due to muscling line (P = 0.46). Weight of LL was 16% greater (P = 0.004) and total protein in LL was 18% greater (P = 0.012) in HighHet than Low steers. ST weight in HighHet was 10% and 13% greater than in High and Low steers (P = 0.007), respectively, and of total ST protein 12% and 17% greater in HighHet than High or Low (P = 0.002). Cross-sectional area (CSA) of LL was greater in HighHet than in High and greater in High than in Low (85.0 vs. 77.0 vs. 70.4 cm2, P < 0.001). Apparent number of myofibers and myofibers per unit CSA did not differ between the muscling lines in LL (P = 0.14) or ST (P = 0.47). Myofiber CSA was greater in the ST of Low than of High and HighHet for type 1 (36% and 31% respectively, P = 0.005) and 2A (22% and 25%, P < 0.001). HighHet steers had greater area of glycolytic (type 2X) relative to more oxidative myofiber types within LL (P = 0.02; 11% and 43% more than High and Low, respectively) and ST (P < 0.001; 27% and 75%). Concentration of RNA in LL was 13% and 10% greater (P = 0.005) in High than in Low and HighHet, respectively, and total amount of RNA in LL was 22% greater in High and 20% greater in HighHet than in Low (P < 0.001). The LL of High steers had less protein to RNA (P = 0.03; 57.4 vs. 65.6) and more RNA to DNA (P = 0.007; 9.03 vs. 7.83) than Low. HighHet steers had 11% more DNA in ST than High (P = 0.04) and 19% more RNA in ST than Low (P = 0.012). The shift towards glycolytic myofibers was consistent with loadings in a principal component that explained 39% of the variation in LL and 38% in ST. Overall, these findings show that selection for increased muscling using live cattle muscle scoring, and 1 copy of the 821 del11 MSTN allele, results in more glycolytic muscle. They also suggest that increased muscling of the High compared with Low steers may be associated with increased translational capacity in the LL.


Assuntos
Bovinos/fisiologia , Miostatina/genética , Carne Vermelha/normas , Alelos , Animais , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Estudos de Coortes , Glicólise , Mutação com Perda de Função , Masculino , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/metabolismo , Miostatina/metabolismo , Oxirredução , RNA/metabolismo
15.
Nat Genet ; 51(6): 990-998, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31133746

RESUMO

The histone acetyl reader bromodomain-containing protein 4 (BRD4) is an important regulator of chromatin structure and transcription, yet factors modulating its activity have remained elusive. Here we describe two complementary screens for genetic and physical interactors of BRD4, which converge on the folate pathway enzyme MTHFD1 (methylenetetrahydrofolate dehydrogenase, cyclohydrolase and formyltetrahydrofolate synthetase 1). We show that a fraction of MTHFD1 resides in the nucleus, where it is recruited to distinct genomic loci by direct interaction with BRD4. Inhibition of either BRD4 or MTHFD1 results in similar changes in nuclear metabolite composition and gene expression; pharmacological inhibitors of the two pathways synergize to impair cancer cell viability in vitro and in vivo. Our finding that MTHFD1 and other metabolic enzymes are chromatin associated suggests a direct role for nuclear metabolism in the control of gene expression.


Assuntos
Ácido Fólico/metabolismo , Regulação da Expressão Gênica , Metilenotetra-Hidrofolato Desidrogenase (NADP)/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Cromatina/genética , Técnicas de Inativação de Genes , Humanos , Mutação com Perda de Função , Ligação Proteica , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Transporte Proteico , Transdução de Sinais , Transcrição Genética
16.
Yakugaku Zasshi ; 139(4): 497-503, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-30930376

RESUMO

Tissue barriers contribute to the maintenance of homeostasis in the body, and tissue barrier dysfunction presents a risk factor for a variety of diseases. The blood-brain barrier (BBB) is a major tissue barrier acting as a static barrier and dynamic interface that plays an important role in the maintenance of central nervous system homeostasis. We show the functional characterization of the brain-to-blood efflux transport system of amyloid-ß peptide (Aß) across the BBB. We found that activated vitamin D3 may be a candidate agent for modulating the Aß clearance across the BBB. Cerebral creatine deficiency syndromes are caused by loss-of-function mutations in the creatine transporter (CRT; SLC6A8), which transports creatine at the BBB. We found that functional impairment of CRT due to a G561R mutation resulted in incomplete N-linked glycosylation due to misfolding during protein maturation, leading to impaired creatine transport activity at the BBB. To develop a delivery system for biomedicine across the tissue barrier, we established a screening system to identify cell-penetrating peptides by a combination of in vitro cell permeability screening assays and phage display technology. Using this system, we identified cyclic hepta-peptides that are able to facilitate intestinal absorption of phages in vitro and in vivo, which are promising candidates as a carrier for macromolecular biomedicines. In conclusion, these studies focusing on the dynamic interface of tissue barriers will contribute to knowledge on disease pathogenesis as well as the development of a targeted biomedicine delivery system.


Assuntos
Barreira Hematoencefálica/metabolismo , Sistemas de Liberação de Medicamentos , Descoberta de Drogas , Doença de Alzheimer/etiologia , Peptídeos beta-Amiloides/metabolismo , Animais , Encefalopatias Metabólicas Congênitas/etiologia , Encefalopatias Metabólicas Congênitas/genética , Colecalciferol/farmacologia , Creatina/deficiência , Creatina/genética , Glicosilação , Humanos , Mutação com Perda de Função , Proteínas de Membrana Transportadoras/genética , Retardo Mental Ligado ao Cromossomo X/etiologia , Retardo Mental Ligado ao Cromossomo X/genética , Proteínas da Membrana Plasmática de Transporte de Neurotransmissores/deficiência , Proteínas da Membrana Plasmática de Transporte de Neurotransmissores/genética
17.
Nat Commun ; 10(1): 1777, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992453

RESUMO

Nerve conduction (NC) studies generate measures of peripheral nerve function that can reveal underlying pathology due to axonal loss, demyelination or both. We perform a genome-wide association study of sural NC amplitude and velocity in 7045 Icelanders and find a low-frequency splice-donor variant in PRPH (c.996+1G>A; MAF = 1.32%) associating with decreased NC amplitude but not velocity. PRPH encodes peripherin, an intermediate filament (IF) protein involved in cytoskeletal development and maintenance of neurons. Through RNA and protein studies, we show that the variant leads to loss-of-function (LoF), as when over-expressed in a cell line devoid of other IFs, it does not allow formation of the normal filamentous structure of peripherin, yielding instead punctate protein inclusions. Recall of carriers for neurological assessment confirms that from an early age, homozygotes have significantly lower sural NC amplitude than non-carriers and are at risk of a mild, early-onset, sensory-negative, axonal polyneuropathy.


Assuntos
Condução Nervosa/genética , Periferinas/genética , Polineuropatias/genética , Sítios de Splice de RNA/genética , Nervo Sural/fisiopatologia , Adulto , Idade de Início , Idoso , Axônios/patologia , Estudos de Casos e Controles , Linhagem Celular , Feminino , Seguimentos , Estudo de Associação Genômica Ampla , Homozigoto , Humanos , Islândia/epidemiologia , Mutação com Perda de Função , Masculino , Pessoa de Meia-Idade , Polineuropatias/epidemiologia , Polineuropatias/fisiopatologia , Prevalência , Processamento de RNA/fisiologia
18.
Nat Commun ; 10(1): 1768, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992454

RESUMO

Seed germination and photoautotrophic establishment are controlled by the antagonistic activity of the phytohormones gibberellins (GAs) and abscisic acid (ABA). Here we show that Arabidopsis thaliana GAS2 (Gain of Function in ABA-modulated Seed Germination 2), a protein belonging to the Fe-dependent 2-oxoglutarate dioxygenase superfamily, catalyzes the stereospecific hydration of GA12 to produce GA12 16, 17-dihydro-16α-ol (DHGA12). We show that DHGA12, a C20-GA has an atypical structure compared to known active GAs but can bind to the GA receptor (GID1c). DHGA12 can promote seed germination, hypocotyl elongation and cotyledon greening. Silencing and over-expression of GAS2 alters the ABA/GA ratio and sensitivity to ABA during seed germination and photoautotrophic establishment. Hence, we propose that GAS2 acts to modulate hormonal balance during early seedling development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Dioxigenases/metabolismo , Giberelinas/metabolismo , Plântula/crescimento & desenvolvimento , Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Dioxigenases/genética , Mutação com Perda de Função , Plantas Geneticamente Modificadas , Sementes/metabolismo
19.
PLoS Genet ; 15(4): e1008039, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30970016

RESUMO

The SWI/SNF-family chromatin remodeling protein ATRX is a tumor suppressor in sarcomas, gliomas and other malignancies. Its loss of function facilitates the alternative lengthening of telomeres (ALT) pathway in tumor cells, while it also affects Polycomb repressive complex 2 (PRC2) silencing of its target genes. To further define the role of inactivating ATRX mutations in carcinogenesis, we knocked out atrx in our previously reported p53/nf1-deficient zebrafish line that develops malignant peripheral nerve sheath tumors and gliomas. Complete inactivation of atrx using CRISPR/Cas9 was lethal in developing fish and resulted in an alpha-thalassemia-like phenotype including reduced alpha-globin expression. In p53/nf1-deficient zebrafish neither peripheral nerve sheath tumors nor gliomas showed accelerated onset in atrx+/- fish, but these fish developed various tumors that were not observed in their atrx+/+ siblings, including epithelioid sarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma and rare types of carcinoma. These cancer types are included in the AACR Genie database of human tumors associated with mutant ATRX, indicating that our zebrafish model reliably mimics a role for ATRX-loss in the early pathogenesis of these human cancer types. RNA-seq of p53/nf1- and p53/nf1/atrx-deficient tumors revealed that down-regulation of telomerase accompanied ALT-mediated lengthening of the telomeres in atrx-mutant samples. Moreover, inactivating mutations in atrx disturbed PRC2-target gene silencing, indicating a connection between ATRX loss and PRC2 dysfunction in cancer development.


Assuntos
Sarcoma Experimental/etiologia , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/genética , Proteína Nuclear Ligada ao X/deficiência , Proteína Nuclear Ligada ao X/genética , Proteínas de Peixe-Zebra/deficiência , Proteínas de Peixe-Zebra/genética , Animais , Animais Geneticamente Modificados , Sistemas CRISPR-Cas , Carcinogênese/genética , Carcinogênese/metabolismo , Modelos Animais de Doenças , Eritropoese , Feminino , Técnicas de Inativação de Genes , Globinas/genética , Humanos , Mutação com Perda de Função , Masculino , Neurofibromina 1/deficiência , Neurofibromina 1/genética , Sarcoma Experimental/genética , Sarcoma Experimental/metabolismo , Homeostase do Telômero/genética , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo
20.
Nat Commun ; 10(1): 1477, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30931947

RESUMO

Phenotypic and biochemical categorization of humans with detrimental variants can provide valuable information on gene function. We illustrate this with the identification of two different homozygous variants resulting in enzymatic loss-of-function in LDHD, encoding lactate dehydrogenase D, in two unrelated patients with elevated D-lactate urinary excretion and plasma concentrations. We establish the role of LDHD by demonstrating that LDHD loss-of-function in zebrafish results in increased concentrations of D-lactate. D-lactate levels are rescued by wildtype LDHD but not by patients' variant LDHD, confirming these variants' loss-of-function effect. This work provides the first in vivo evidence that LDHD is responsible for human D-lactate metabolism. This broadens the differential diagnosis of D-lactic acidosis, an increasingly recognized complication of short bowel syndrome with unpredictable onset and severity. With the expanding incidence of intestinal resection for disease or obesity, the elucidation of this metabolic pathway may have relevance for those patients with D-lactic acidosis.


Assuntos
Acidose Láctica/diagnóstico , Lactato Desidrogenases/genética , Ácido Láctico/metabolismo , Mutação com Perda de Função , Síndrome do Intestino Curto/metabolismo , Espasmos Infantis/diagnóstico , Acidose Láctica/genética , Adulto , Animais , Consanguinidade , Diagnóstico Diferencial , Homozigoto , Humanos , Lactente , Lactato Desidrogenases/deficiência , Masculino , Espasmos Infantis/genética , Peixe-Zebra
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