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1.
Mol Cell ; 84(3): 463-475.e5, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38242128

RESUMO

Type I CRISPR-Cas systems utilize the RNA-guided Cascade complex to identify matching DNA targets and the nuclease-helicase Cas3 to degrade them. Among the seven subtypes, type I-C is compact in size and highly active in creating large-sized genome deletions in human cells. Here, we use four cryoelectron microscopy snapshots to define its RNA-guided DNA binding and cleavage mechanisms in high resolution. The non-target DNA strand (NTS) is accommodated by I-C Cascade in a continuous binding groove along the juxtaposed Cas11 subunits. Binding of Cas3 further traps a flexible bulge in NTS, enabling NTS nicking. We identified two anti-CRISPR proteins AcrIC8 and AcrIC9 that strongly inhibit Neisseria lactamica I-C function. Structural analysis showed that AcrIC8 inhibits PAM recognition through allosteric inhibition, whereas AcrIC9 achieves so through direct competition. Both Acrs potently inhibit I-C-mediated genome editing and transcriptional modulation in human cells, providing the first off-switches for type I CRISPR eukaryotic genome engineering.


Assuntos
Proteínas Associadas a CRISPR , Edição de Genes , Humanos , Sistemas CRISPR-Cas , Microscopia Crioeletrônica , Proteínas Associadas a CRISPR/metabolismo , DNA/metabolismo , RNA
2.
Mol Cell ; 82(15): 2754-2768.e5, 2022 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-35835111

RESUMO

Type I CRISPR-Cas systems typically rely on a two-step process to degrade DNA. First, an RNA-guided complex named Cascade identifies the complementary DNA target. The helicase-nuclease fusion enzyme Cas3 is then recruited in trans for processive DNA degradation. Contrary to this model, here, we show that type I-A Cascade and Cas3 function as an integral effector complex. We provide four cryoelectron microscopy (cryo-EM) snapshots of the Pyrococcus furiosus (Pfu) type I-A effector complex in different stages of DNA recognition and degradation. The HD nuclease of Cas3 is autoinhibited inside the effector complex. It is only allosterically activated upon full R-loop formation, when the entire targeted region has been validated by the RNA guide. The mechanistic insights inspired us to convert Pfu Cascade-Cas3 into a high-sensitivity, low-background, and temperature-activated nucleic acid detection tool. Moreover, Pfu CRISPR-Cas3 shows robust bi-directional deletion-editing activity in human cells, which could find usage in allele-specific inactivation of disease-causing mutations.


Assuntos
Proteínas Associadas a CRISPR , Proteínas Associadas a CRISPR/genética , Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Microscopia Crioeletrônica , DNA/genética , DNA/metabolismo , Endonucleases/genética , Edição de Genes , Humanos , RNA
3.
Nature ; 598(7881): 515-520, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34588691

RESUMO

Prokaryotes adapt to challenges from mobile genetic elements by integrating spacers derived from foreign DNA in the CRISPR array1. Spacer insertion is carried out by the Cas1-Cas2 integrase complex2-4. A substantial fraction of CRISPR-Cas systems use a Fe-S cluster containing Cas4 nuclease to ensure that spacers are acquired from DNA flanked by a protospacer adjacent motif (PAM)5,6 and inserted into the CRISPR array unidirectionally, so that the transcribed CRISPR RNA can guide target searching in a PAM-dependent manner. Here we provide a high-resolution mechanistic explanation for the Cas4-assisted PAM selection, spacer biogenesis and directional integration by type I-G CRISPR in Geobacter sulfurreducens, in which Cas4 is naturally fused with Cas1, forming Cas4/Cas1. During biogenesis, only DNA duplexes possessing a PAM-embedded 3'-overhang trigger Cas4/Cas1-Cas2 assembly. During this process, the PAM overhang is specifically recognized and sequestered, but is not cleaved by Cas4. This 'molecular constipation' prevents the PAM-side prespacer from participating in integration. Lacking such sequestration, the non-PAM overhang is trimmed by host nucleases and integrated to the leader-side CRISPR repeat. Half-integration subsequently triggers PAM cleavage and Cas4 dissociation, allowing spacer-side integration. Overall, the intricate molecular interaction between Cas4 and Cas1-Cas2 selects PAM-containing prespacers for integration and couples the timing of PAM processing with the stepwise integration to establish directionality.


Assuntos
Proteínas Associadas a CRISPR/metabolismo , Sistemas CRISPR-Cas , Endonucleases/metabolismo , Geobacter/enzimologia , Bases de Dados Genéticas , Modelos Moleculares , Conformação Molecular , Motivos de Nucleotídeos
4.
Mol Cell ; 65(5): 801-817.e4, 2017 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-28216226

RESUMO

Telomeres employ TRF2 to protect chromosome ends from activating the DNA damage sensor MRE11-RAD50-NBS1 (MRN), thereby repressing ATM-dependent DNA damage checkpoint responses. How TRF2 prevents MRN activation at dysfunctional telomeres is unclear. Here, we show that the phosphorylation status of NBS1 determines the repair pathway choice of dysfunctional telomeres. The crystal structure of the TRF2-NBS1 complex at 3.0 Å resolution shows that the NBS1 429YQLSP433 motif interacts specifically with the TRF2TRFH domain. Phosphorylation of NBS1 serine 432 by CDK2 in S/G2 dissociates NBS1 from TRF2, promoting TRF2-Apollo/SNM1B complex formation and the protection of leading-strand telomeres. Classical-NHEJ-mediated repair of telomeres lacking TRF2 requires phosphorylated NBS1S432 to activate ATM, while interaction of de-phosphorylated NBS1S432 with TRF2 promotes alternative-NHEJ repair of telomeres lacking POT1-TPP1. Our work advances understanding of how the TRF2TRFH domain orchestrates telomere end protection and reveals how the phosphorylation status of the NBS1S432 dictates repair pathway choice of dysfunctional telomeres.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades , Proteínas Nucleares/metabolismo , Telômero/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/metabolismo , Aminopeptidases/genética , Aminopeptidases/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sítios de Ligação , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Quinase 2 Dependente de Ciclina/genética , Quinase 2 Dependente de Ciclina/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA , Dipeptidil Peptidases e Tripeptidil Peptidases/genética , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Exodesoxirribonucleases , Fase G1 , Fase G2 , Células HCT116 , Humanos , Proteínas Inibidoras de Apoptose/genética , Proteínas Inibidoras de Apoptose/metabolismo , Modelos Moleculares , Proteínas Nucleares/química , Proteínas Nucleares/genética , Fosforilação , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Fase S , Serina Proteases/genética , Serina Proteases/metabolismo , Complexo Shelterina , Relação Estrutura-Atividade , Telômero/genética , Telômero/patologia , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a Telômeros/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/química , Proteína 2 de Ligação a Repetições Teloméricas/genética
5.
Biochem Biophys Res Commun ; 732: 150406, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39032412

RESUMO

Lignocellulose, the most abundant organic waste on Earth, is of economic value because it can be converted into biofuels like ethanol by enzymes such as ß-glucosidase. This study involved cloning a ß-glucosidase gene named JBG from the rumen fungus Neocallimastix patriciarum J11. When expressed recombinantly in Escherichia coli, the rJBG enzyme exhibited significant activity, hydrolyzing 4-nitrophenyl-ß-d-glucopyranoside and cellobiose to release glucose. Surprisingly, the rJBG enzyme also showed hydrolytic activity against ß-glucan, breaking it down into glucose, indicating that the rJBG enzyme possesses both ß-glucosidase and ß-glucanase activities, a characteristic rarely found in ß-glucosidases. When the JBG gene was expressed in Saccharomyces cerevisiae and the transformants were inoculated into a medium containing ß-glucan as the sole carbon source, the ethanol concentration in the culture medium increased from 0.17 g/L on the first day to 0.77 g/L on the third day, reaching 1.3 g/L on the fifth day, whereas no ethanol was detected in the yeast transformants containing the recombinant plasmid pYES-Sur under the same conditions. These results demonstrate that yeast transformants carrying the JBG gene can directly saccharify ß-glucan and ferment it to produce ethanol. This gene, with its dual ß-glucosidase and ß-glucanase activities, simplifies and reduces the cost of the typical process of converting lignocellulose into bioethanol using enzymes and yeast.

6.
Molecules ; 28(15)2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37570647

RESUMO

Fish bone fermented using Monascus purpureus (FBF) has total phenols and functional amino acids that contribute to its anti-oxidant and anti-inflammatory properties. Colorectal cancer, one of the most prevalent cancers and the third largest cause of death worldwide, has become a serious threat to global health. This study investigates the anti-cancer effects of FBF (1, 2.5 or 5 mg/mL) on the cell growth and molecular mechanism of HCT-116 cells. The HCT-116 cell treatment with 2.5 or 5 mg/mL of FBF for 24 h significantly decreased cell viability (p < 0.05). The S and G2/M phases significantly increased by 88-105% and 25-43%, respectively (p < 0.05). Additionally, FBF increased the mRNA expression of caspase 8 (38-77%), protein expression of caspase 3 (34-94%), poly (ADP-ribose) polymerase (PARP) (31-34%) and induced apoptosis (236-773%) of HCT-116 cells (p < 0.05). FBF also increased microtubule-associated protein 1B light chain 3 (LC3) (38-48%) and phosphoinositide 3 kinase class III (PI3K III) (32-53%) protein expression, thereby inducing autophagy (26-52%) of HCT-116 cells (p < 0.05). These results showed that FBF could inhibit HCT-116 cell growth by inducing S and G2/M phase arrest of the cell cycle, apoptosis and autophagy. Thus, FBF has the potential to treat colorectal cancer.


Assuntos
Neoplasias Colorretais , Monascus , Animais , Humanos , Fosfatidilinositol 3-Quinases , Linhagem Celular Tumoral , Apoptose , Neoplasias Colorretais/tratamento farmacológico , Autofagia
7.
J Food Sci Technol ; 60(3): 958-965, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36908357

RESUMO

Fish bones are the by-products of aquatic and fishery processing, which are often discarded. However, it has been considered having health-promoting by containing many essential nutrients. This study investigates the anti-inflammatory effect of fish bone fermented by Monascus purpureus (FBF) and the NF-κB pathway regulation mechanism in lipopolysaccharides (LPS)-induced RAW 264.7 cells. FBF has inhibited the production of PGE2 (prostaglandin E2), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in LPS-induced RAW264.7 cells. The FBF has significantly inhibited mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, FBF has suppressed activation of NF-κB (nuclear factor kappa-B) by increasing IκB mRNA expression and reduced of p65, p50 mRNA expression, as well as nuclear NF-κB DNA binding activity in LPS-induced RAW 246.7 cells. These findings demonstrate that FBF has inhibited LPS-induced inflammation by subsiding the activation of NF-κB in RAW 246.7 cells, implying that FBF could be employed as a promising natural product.

8.
Nature ; 530(7591): 447-52, 2016 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-26886794

RESUMO

The mixed lineage leukaemia (MLL) family of proteins (including MLL1-MLL4, SET1A and SET1B) specifically methylate histone 3 Lys4, and have pivotal roles in the transcriptional regulation of genes involved in haematopoiesis and development. The methyltransferase activity of MLL1, by itself severely compromised, is stimulated by the three conserved factors WDR5, RBBP5 and ASH2L, which are shared by all MLL family complexes. However, the molecular mechanism of how these factors regulate the activity of MLL proteins still remains poorly understood. Here we show that a minimized human RBBP5-ASH2L heterodimer is the structural unit that interacts with and activates all MLL family histone methyltransferases. Our structural, biochemical and computational analyses reveal a two-step activation mechanism of MLL family proteins. These findings provide unprecedented insights into the common theme and functional plasticity in complex assembly and activity regulation of MLL family methyltransferases, and also suggest a universal regulation mechanism for most histone methyltransferases.


Assuntos
Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Histona-Lisina N-Metiltransferase/química , Histona-Lisina N-Metiltransferase/metabolismo , Proteína de Leucina Linfoide-Mieloide/química , Proteína de Leucina Linfoide-Mieloide/metabolismo , Sequência de Aminoácidos , Cristalografia por Raios X , Ativação Enzimática , Histona-Lisina N-Metiltransferase/genética , Histonas/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Modelos Moleculares , Dados de Sequência Molecular , Complexos Multiproteicos , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Ligação Proteica , Estrutura Quaternária de Proteína , Estrutura Terciária de Proteína , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
9.
Int J Mol Sci ; 23(10)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35628265

RESUMO

As a conventional medical dressing, medical gauze does not adequately protect complex and hard-to-heal diabetic wounds and is likely to permit bacterial entry and infections. Therefore, it is necessary to develop novel dressings to promote wound healing in diabetic patients. Komagataeibacter intermedius was used to produce unmodified bacterial cellulose, which is rarely applied directly to diabetic wounds. The produced cellulose was evaluated for wound recovery rate, level of inflammation, epidermal histopathology, and antimicrobial activities in treated wounds. Diabetic mices' wounds treated with bacterial cellulose healed 1.63 times faster than those treated with gauze; the values for the skin indicators in bacterial cellulose treated wounds were more significant than those treated with gauze. Bacterial cellulose was more effective than gauze in promoting tissue proliferation with more complete epidermal layers and the formation of compact collagen in the histological examination. Moreover, wounds treated with bacterial cellulose alone had less water and glucose content than those treated with gauze; this led to an increase of 6.82 times in antimicrobial protection, lower levels of TNF-α and IL-6 (39.6% and 83.2%), and higher levels of IL-10 (2.07 times) than in mice wounds treated with gauze. The results show that bacterial cellulose produced using K. intermedius beneficially affects diabetic wound healing and creates a hygienic microenvironment by preventing inflammation. We suggest that bacterial cellulose can replace medical gauze as a wound dressing for diabetic patients.


Assuntos
Celulose , Diabetes Mellitus Experimental , Acetobacteraceae , Animais , Celulose/farmacologia , Humanos , Inflamação , Camundongos , Cicatrização
10.
Nucleic Acids Res ; 47(3): 1573-1584, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30462301

RESUMO

The dynamic association of chromosomes with the nuclear envelope (NE) is essential for chromosome maintenance. Schizosaccharomyces pombe inner nuclear membrane protein Bqt4 plays a critical role in connecting telomeres to the NE, mainly through a direct interaction with the telomeric protein Rap1. Bqt4 also interacts with Lem2 for pericentric heterochromatin maintenance. How Bqt4 coordinates the interactions with different proteins to exert their functions is unclear. Here, we report the crystal structures of the N-terminal domain of Bqt4 in complexes with Bqt4-binding motifs from Rap1, Lem2, and Sad1. The structural, biochemical and cellular analyses reveal that the N-terminal domain of Bqt4 is a protein-interaction module that recognizes a consensus motif and plays essential roles in telomere-NE association and meiosis progression. Phosphorylation of Bqt4-interacting proteins may act as a switch to regulate these interactions during cell cycles. Our studies provide structural insights into the identification and regulation of Bqt4-mediated interactions.


Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Membrana/genética , Membrana Nuclear/genética , Proteínas Nucleares/genética , Proteínas de Schizosaccharomyces pombe/genética , Schizosaccharomyces/genética , Telômero/genética , Cromossomos Fúngicos/genética , Proteínas de Ligação a DNA/química , Proteínas de Membrana/química , Membrana Nuclear/química , Proteínas Nucleares/química , Fosforilação , Mapas de Interação de Proteínas/genética , Schizosaccharomyces/química , Proteínas de Schizosaccharomyces pombe/química
11.
Int J Mol Sci ; 22(23)2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34884465

RESUMO

Rhizopus oryzae is a fungus used to ferment tempeh in Indonesia and is generally recognized as safe (GRAS) for human consumption by the USA FDA. We previously assessed the effect of a tempeh extract on cortisol levels in zebrafish but did not include behavioral studies. Here, we measured the GABA content in three strains of Rhizopus oryzae, two isolated by us (MHU 001 and MHU 002) and one purchased. We then investigated the effect of tempeh on cortisol and the gut microbiota in a zebrafish experimental model. GABA concentration was the highest in MHU 002 (9.712 ± 0.404 g kg-1) followed by our MHU 001 strain and the purchased one. The fish were divided into one control group fed a normal diet and three experimental groups fed soybean tempeh fermented with one of the three strains of Rhizopus oryzae. After two weeks, individual fish were subjected to unpredicted chronic stress using the novel tank diving test and the tank light-dark test. Next-generation sequencing was used to analyze gut microbial communities and RT-PCR to analyze the expression of BDNF (brain-derived neurotrophic factor) gene and of other genes involved in serotonin signaling/metabolism in gut and brain. Tempeh-fed zebrafish exhibited increased exploratory behavior (less stress) in both tank tests. They also had significantly reduced gut Proteobacteria (include E. coli) (51.90% vs. 84.97%) and significantly increased gut Actinobacteria (include Bifidobacterium spp.) (1.80% vs. 0.79%). The content of Bifidobacteriumadolescentis, a "psychobiotic", increased ten-fold from 0.04% to 0.45%. Tempeh also increases BDNF levels in zebrafish brain. Rhizopus oryzae MHU 001 greatly improved the anti-stress effect of tempeh and microbiota composition in zebrafish gut.


Assuntos
Bactérias/classificação , DNA Bacteriano/genética , Rhizopus oryzae/fisiologia , Alimentos de Soja/microbiologia , Peixe-Zebra/fisiologia , Ração Animal/microbiologia , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Fator Neurotrófico Derivado do Encéfalo/genética , Fermentação , Microbioma Gastrointestinal , Sequenciamento de Nucleotídeos em Larga Escala , Hidrocortisona/análise , Rhizopus oryzae/química , Rhizopus oryzae/classificação , Análise de Sequência de DNA , Estresse Fisiológico , Proteínas de Peixe-Zebra/genética , Ácido gama-Aminobutírico/análise
12.
J Pineal Res ; 68(1): e12618, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31631405

RESUMO

Previous studies confirmed that melatonin regulates Runx2 expression but the mechanism is unclear. There is a direct interaction between Runx2 and the vitamin D receptor (VDR). Herein, we observed a direct interaction between melatonin and the VDR but not Runx2 using isothermal titration calorimetry. Furthermore, this direct binding was detected only in the C-terminal ligand binding domain (LBD) of the VDR but not in the N-terminal DNA-binding domain (DBD) or the hinge region. Spectrophotometry indicated that melatonin and vitamin D3 (VD3) had similar uptake rates, but melatonin's uptake was significantly inhibited by VD3 until the concentration of melatonin was obviously higher than that of VD3 in a preosteoblastic cell line MC3T3-E1. GST pull-down and yeast two-hybrid assay showed that the interactive smallest fragments were on the 319-379 position of Runx2 and the N-terminus 110-amino acid DBD of the VDR. Electrophoretic mobility shift assay (EMSA) demonstrated that Runx2 facilitated the affinity between the VDR and its specific DNA substrate, which was further documented by a fluorescent EMSA assay where Cy3 labeled Runx2 co-localized with the VDR-DNA complex. Another fluorescent EMSA assay confirmed that the binding of the VDR to Runx2 was significantly enhanced with an increasing concentrations of the VDR, especially in the presence of melatonin; it was further documented using a co-immunoprecipitation assay that this direct interaction was markedly enhanced by melatonin treatment in the MC3T3-E1 cells. Thus, the VDR is a novel melatonin-binding nuclear receptor, and melatonin indirectly regulates Runx2 when it directly binds to the LBD and the DBD of the VDR, respectively.


Assuntos
Melatonina , Receptores de Calcitriol , Animais , Linhagem Celular , Subunidade alfa 1 de Fator de Ligação ao Core/química , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Células HEK293 , Humanos , Melatonina/química , Melatonina/metabolismo , Camundongos , Ligação Proteica , Domínios Proteicos , Receptores de Calcitriol/química , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo
14.
Sci China Life Sci ; 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-39012436

RESUMO

The CRISPR-Cas system, an adaptive immunity system in prokaryotes designed to combat phages and foreign nucleic acids, has evolved into a groundbreaking technology enabling gene knockout, large-scale gene insertion, base editing, and nucleic acid detection. Despite its transformative impact, the conventional CRISPR-Cas effectors face a significant hurdle-their size poses challenges in effective delivery into organisms and cells. Recognizing this limitation, the imperative arises for the development of compact and miniature gene editors to propel advancements in gene-editing-related therapies. Two strategies were accepted to develop compact genome editors: harnessing OMEGA (Obligate Mobile Element-guided Activity) systems, or engineering the existing CRISPR-Cas system. In this review, we focus on the advances in miniature genome editors based on both of these strategies. The objective is to unveil unprecedented opportunities in genome editing by embracing smaller, yet highly efficient genome editors, promising a future characterized by enhanced precision and adaptability in the genetic interventions.

15.
Nat Commun ; 15(1): 4322, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38773107

RESUMO

Heterochromatin is generally associated with the nuclear periphery, but how the spatial organization of heterochromatin is regulated to ensure epigenetic silencing remains unclear. Here we found that Sad1, an inner nuclear membrane SUN-family protein in fission yeast, interacts with histone H2A-H2B but not H3-H4. We solved the crystal structure of the histone binding motif (HBM) of Sad1 in complex with H2A-H2B, revealing the intimate contacts between Sad1HBM and H2A-H2B. Structure-based mutagenesis studies revealed that the H2A-H2B-binding activity of Sad1 is required for the dynamic distribution of Sad1 throughout the nuclear envelope (NE). The Sad1-H2A-H2B complex mediates tethering telomeres and the mating-type locus to the NE. This complex is also important for heterochromatin silencing. Mechanistically, H2A-H2B enhances the interaction between Sad1 and HDACs, including Clr3 and Sir2, to maintain epigenetic identity of heterochromatin. Interestingly, our results suggest that Sad1 exhibits the histone-enhanced liquid-liquid phase separation property, which helps recruit heterochromatin factors to the NE. Our results uncover an unexpected role of SUN-family proteins in heterochromatin regulation and suggest a nucleosome-independent role of H2A-H2B in regulating Sad1's functionality.


Assuntos
Heterocromatina , Histonas , Ligação Proteica , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Heterocromatina/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/química , Histonas/metabolismo , Schizosaccharomyces/metabolismo , Schizosaccharomyces/genética , Telômero/metabolismo , Telômero/genética , Membrana Nuclear/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Histona Desacetilases/metabolismo , Histona Desacetilases/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Cristalografia por Raios X
16.
Nat Commun ; 15(1): 4126, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750051

RESUMO

Type I CRISPR-Cas systems employ multi-subunit effector Cascade and helicase-nuclease Cas3 to target and degrade foreign nucleic acids, representing the most abundant RNA-guided adaptive immune systems in prokaryotes. Their ability to cause long fragment deletions have led to increasing interests in eukaryotic genome editing. While the Cascade structures of all other six type I systems have been determined, the structure of the most evolutionarily conserved type I-B Cascade is still missing. Here, we present two cryo-EM structures of the Synechocystis sp. PCC 6714 (Syn) type I-B Cascade, revealing the molecular mechanisms that underlie RNA-directed Cascade assembly, target DNA recognition, and local conformational changes of the effector complex upon R-loop formation. Remarkably, a loop of Cas5 directly intercalated into the major groove of the PAM and facilitated PAM recognition. We further characterized the genome editing profiles of this I-B Cascade-Cas3 in human CD3+ T cells using mRNA-mediated delivery, which led to unidirectional 4.5 kb deletion in TRAC locus and achieved an editing efficiency up to 41.2%. Our study provides the structural basis for understanding target DNA recognition by type I-B Cascade and lays foundation for harnessing this system for long range genome editing in human T cells.


Assuntos
Sistemas CRISPR-Cas , Microscopia Crioeletrônica , Edição de Genes , Synechocystis , Edição de Genes/métodos , Humanos , Synechocystis/genética , Proteínas Associadas a CRISPR/metabolismo , Proteínas Associadas a CRISPR/genética , Proteínas Associadas a CRISPR/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Linfócitos T/metabolismo , Estruturas R-Loop/genética
17.
Commun Biol ; 7(1): 858, 2024 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-39003402

RESUMO

R-loop-triggered collateral single-stranded DNA (ssDNA) nuclease activity within Class 1 Type I CRISPR-Cas systems holds immense potential for nucleic acid detection. However, the hyperactive ssDNase activity of Cas3 introduces unwanted noise and false-positive results. In this study, we identified a novel Type I-A Cas3 variant derived from Thermococcus siculi, which remains in an auto-inhibited state until it is triggered by Cascade complex and R-loop formation. This Type I-A CRISPR-Cas3 system not only exhibits an expanded protospacer adjacent motif (PAM) recognition capability but also demonstrates remarkable intolerance towards mismatched sequences. Furthermore, it exhibits dual activation modes-responding to both DNA and RNA targets. The culmination of our research efforts has led to the development of the Hyper-Active-Verification Establishment (HAVE, ). This innovation enables swift and precise human papillomavirus (HPV) diagnosis in clinical samples, providing a robust molecular diagnostic tool based on the Type I-A CRISPR-Cas3 system. Our findings contribute to understanding type I-A CRISPR-Cas3 system regulation and facilitate the creation of advanced diagnostic solutions with broad clinical applicability.


Assuntos
Sistemas CRISPR-Cas , Infecções por Papillomavirus , Humanos , Infecções por Papillomavirus/diagnóstico , Infecções por Papillomavirus/virologia , Infecções por Papillomavirus/genética , Papillomaviridae/genética , Proteínas Associadas a CRISPR/metabolismo , Proteínas Associadas a CRISPR/genética , Papillomavirus Humano
18.
Nat Commun ; 15(1): 831, 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38280857

RESUMO

Transposon-associated ribonucleoprotein TnpB is known to be the ancestry endonuclease of diverse Cas12 effector proteins from type-V CRISPR system. Given its small size (408 aa), it is of interest to examine whether engineered TnpB could be used for efficient mammalian genome editing. Here, we showed that the gene editing activity of native TnpB from Deinococcus radiodurans (ISDra2 TnpB) in mouse embryos was already higher than previously identified small-sized Cas12f1. Further stepwise engineering of noncoding RNA (ωRNA or reRNA) component of TnpB significantly elevated the nuclease activity of TnpB. Notably, an optimized TnpB-ωRNA system could be efficiently delivered in vivo with single adeno-associated virus (AAV) and corrected the disease phenotype in a tyrosinaemia mouse model. Thus, the engineered miniature TnpB system represents a new addition to the current genome editing toolbox, with the unique feature of the smallest effector size that facilitate efficient AAV delivery for editing of cells and tissues.


Assuntos
Edição de Genes , Tirosinemias , Camundongos , Animais , Sistemas CRISPR-Cas/genética , Tirosinemias/genética , Tirosinemias/terapia , Mamíferos
19.
J Vet Sci ; 24(2): e29, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37012037

RESUMO

BACKGROUND: Feline panleukopenia virus (FPV) is a widespread and highly infectious pathogen in cats with a high mortality rate. Although Yanji has a developed cat breeding industry, the variation of FPV locally is still unclear. OBJECTIVES: This study aimed to isolate and investigate the epidemiology of FPV in Yanji between 2021 and 2022. METHODS: A strain of FPV was isolated from F81 cells. Cats suspected of FPV infection (n = 80) between 2021 and 2022 from Yanji were enrolled in this study. The capsid protein 2 (VP2) of FPV was amplified. It was cloned into the pMD-19T vector and transformed into a competent Escherichia coli strain. The positive colonies were analyzed via VP2 Sanger sequencing. A phylogenetic analysis based on a VP2 coding sequence was performed to identify the genetic relationships between the strains. RESULTS: An FPV strain named YBYJ-1 was successfully isolated. The virus diameter was approximately 20-24 nm, 50% tissue culture infectious dose = 1 × 10-4.94/mL, which caused cytopathic effect in F81 cells. The epidemiological survey from 2021 to 2022 showed that 27 of the 80 samples were FPV-positive. Additionally, three strains positive for CPV-2c were unexpectedly found. Phylogenetic analysis showed that most of the 27 FPV strains belonged to the same group, and no mutations were found in the critical amino acids. CONCLUSIONS: A local FPV strain named YBYJ-1 was successfully isolated. There was no critical mutation in FPV in Yanji, but some cases with CPV-2c infected cats were identified.


Assuntos
Doenças do Gato , Panleucopenia Felina , Animais , Gatos , China/epidemiologia , Panleucopenia Felina/epidemiologia , Vírus da Panleucopenia Felina/genética , Epidemiologia Molecular , Filogenia
20.
ACS Appl Bio Mater ; 6(12): 5768-5775, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38029407

RESUMO

Flexible wearable strain sensors have shown great potential in monitoring human motion, due to their ability to flexibly fit to multiple surfaces, which can realize the monitoring of human motions and external stimulation. However, the utilization of the sensor in extreme conditions such as low or high temperatures still poses a risk of signal output distortion. Moreover, the continuous usage of the sensor may result in extensive bacterial growth at the interface between the sensor and the skin, posing a threat to human health. Herein, a hydrophobic flexible antibacterial strain sensor (CGP) based on carbon black-PDMS was prepared, inspired by the superhydrophobic surface of a lotus leaf. The CGP sensor demonstrates exceptional sensitivity, with a gauge factor (GF) of 0.467 in the strain range of 0-15% and a fast response time (65.4 ms, 5% strain). Additionally, it exhibits a high conductivity of 1.2 mS cm-1 at -20 °C and 2.0 mS cm-1 at 100 °C, indicating its ability to function effectively even in extreme temperatures. The static water contact angle of CGP measures 121.7°, and self-cleaning experiments have confirmed its excellent self-cleaning performance. Furthermore, the CGP displays distinct response characteristics to movements of human fingers, wrists, and knees, making it an ideal choice for monitoring various joints in the human body. In terms of antibacterial properties, CGP has demonstrated an antibacterial rate of over 99% against E. coli and S. aureus. Possessing high sensitivity, superior electrical conductivity in harsh environments, and super antibacterial capabilities, CGP holds significant potential for applications in human motion monitoring and other fields.


Assuntos
Dispositivos Eletrônicos Vestíveis , Humanos , Escherichia coli , Staphylococcus aureus , Pele , Antibacterianos/farmacologia
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