Nucleic Acids Research最新文献

{"title":"Oxidative damage within alternative DNA structures results in aberrant mutagenic processing.","authors":"Maha Zewail-Foote, Imee M A Del Mundo, Alex W Klattenhoff, Karen M Vasquez","doi":"10.1093/nar/gkaf066","DOIUrl":"https://doi.org/10.1093/nar/gkaf066","url":null,"abstract":"<p><p>Genetic instability is a hallmark of cancer, and mutation hotspots in human cancer genomes co-localize with alternative DNA structure-forming sequences (e.g. H-DNA), implicating them in cancer etiology. H-DNA has been shown to stimulate genetic instability in mammals. Here, we demonstrate a new paradigm of genetic instability, where a cancer-associated H-DNA-forming sequence accumulates more oxidative lesions than B-DNA under conditions of oxidative stress (OS), often found in tumor microenvironments. We show that OS results in destabilization of the H-DNA structure and attenuates the fold increase in H-DNA-induced mutations over control B-DNA in mammalian cells. Furthermore, the mutation spectra revealed that the damaged H-DNA-containing region was processed differently compared to H-DNA in the absence of oxidative damage in mammalian cells. The oxidatively modified H-DNA elicits differential recruitment of DNA repair proteins from both the base excision repair and nucleotide excision repair mechanisms. Altogether, these results suggest a new model of genetic instability whereby H-DNA-forming regions are hotspots for DNA damage in oxidative microenvironments, resulting in its altered mutagenic processing. Our findings provide valuable insights into the role of OS in DNA structure-induced genetic instability and may establish H-DNA-forming sequences as promising genomic biomarkers and potential therapeutic targets for genetic diseases.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The human genome encodes a multitude of novel miRNAs.","authors":"Fan Gao, Fang Wang, Yue Chen, Bolin Deng, Fujian Yang, Huifen Cao, Junjie Chen, Huiling Chen, Fei Qi, Philipp Kapranov","doi":"10.1093/nar/gkaf070","DOIUrl":"https://doi.org/10.1093/nar/gkaf070","url":null,"abstract":"<p><p>Human cells generate a vast complexity of noncoding RNAs, the \"RNA dark matter,\" which includes a vast small RNA (sRNA) transcriptome. The biogenesis, biological relevance, and mechanisms of action of most of these transcripts remain unknown, and they are widely assumed to represent degradation products. Here, we aimed to functionally characterize human sRNA transcriptome by attempting to answer the following question-can a significant number of novel sRNAs correspond to novel members of known classes, specifically, microRNAs (miRNAs)? By developing and validating a miRNA discovery pipeline, we show that at least 2726 novel canonical miRNAs, majority of which represent novel miRNA families, exist in just one human cell line compared to just 1914 known miRNA loci. Moreover, potentially tens of thousands of miRNAs remain to be discovered. Strikingly, many novel miRNAs map to exons of protein-coding genes emphasizing a complex and interleaved architecture of the genome. The existence of so many novel members of a functional class of sRNAs suggest that the human sRNA transcriptome harbors a multitude of novel regulatory molecules. Overall, these results suggest that we are at the very beginning of understanding the true functional complexity of the sRNA component of the \"RNA dark matter.\"</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crossovers are regulated by a conserved and disordered synaptonemal complex domain.","authors":"Ana Rita Rodrigues Neves, Ivana Čavka, Tobias Rausch, Simone Köhler","doi":"10.1093/nar/gkaf095","DOIUrl":"10.1093/nar/gkaf095","url":null,"abstract":"<p><p>During meiosis, the number and distribution of crossovers (COs) must be precisely regulated through CO assurance and interference to prevent chromosome missegregation and genomic instability in the progeny. Here we show that this regulation of COs depends on a disordered and conserved domain within the synaptonemal complex (SC). This domain is located at the C-terminus of the central element protein SYP-4 in Caenorhabditis elegans. While not necessary for synapsis, the C-terminus of SYP-4 is crucial for both CO assurance and interference. Although the SYP-4 C-terminus contains many potential phosphorylation sites, we found that phosphorylation is not the primary regulator of CO events. Instead, we discovered that nine conserved phenylalanines are required to recruit a pro-CO factor predicted to be an E3 ligase and regulate the physical properties of the SC. We propose that this conserved and disordered domain plays a crucial role in maintaining the SC in a state that allows transmitting signals to regulate CO formation. While the underlying mechanisms remain to be fully understood, our findings align with existing models suggesting that the SC plays a critical role in determining the number and distribution of COs along chromosomes, thereby safeguarding the genome for future generations.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11833701/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The epigenetic landscape shapes smoking-induced mutagenesis by modulating DNA damage susceptibility and repair efficiency.","authors":"Elisheva E Heilbrun, Dana Tseitline, Hana Wasserman, Ayala Kirshenbaum, Yuval Cohen, Raluca Gordan, Sheera Adar","doi":"10.1093/nar/gkaf048","DOIUrl":"10.1093/nar/gkaf048","url":null,"abstract":"<p><p>Lung cancer sequencing efforts have uncovered mutational signatures that are attributed to exposure to the cigarette smoke carcinogen benzo[a]pyrene. Benzo[a]pyrene metabolizes in cells to benzo[a]pyrene diol epoxide (BPDE) and reacts with guanine nucleotides to form bulky BPDE adducts. These DNA adducts block transcription and replication, compromising cell function and survival, and are repaired in human cells by the nucleotide excision repair pathway. Here, we applied high-resolution genomic assays to measure BPDE-induced damage formation and mutagenesis in human cells. We integrated the new damage and mutagenesis data with previous repair, DNA methylation, RNA expression, DNA replication, and chromatin component measurements in the same cell lines, along with lung cancer mutagenesis data. BPDE damage formation is significantly enhanced by DNA methylation and in accessible chromatin regions, including transcribed and early-replicating regions. Binding of transcription factors is associated primarily with reduced, but also enhanced damage formation, depending on the factor. While DNA methylation does not appear to influence repair efficiency, this repair was significantly elevated in accessible chromatin regions, which accumulated fewer mutations. Thus, when damage and repair drive mutagenesis in opposing directions, the final mutational patterns appear to be dictated by the efficiency of repair rather than the frequency of underlying damages.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11811737/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143399071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A plasmid-encoded inactive toxin-antitoxin system MtvT/MtvA regulates plasmid conjugative transfer and bacterial virulence in Pseudomonas aeruginosa.","authors":"Meng Li, Hua Guo, Lecheng Wang, Ruixue Tao, Gaoyu Song, Linke Cao, Wenbo Yan, Ziyuan Wu, Qian Liu, Yaodong Chen, Lei Gong, Tietao Wang, Yani Zhang","doi":"10.1093/nar/gkaf075","DOIUrl":"10.1093/nar/gkaf075","url":null,"abstract":"<p><p>Plasmid-encoded toxin-antitoxin (TA) systems are known for their role in plasmid maintenance via post-segregational killing. Here, we identified an inactive type II TA system, MtvT/MtvA (MtvTA), encoded on the conjugative plasmid pPAD8 from the clinical Pseudomonas aeruginosa strain PAD8. Despite its annotation as a toxin, MtvT exhibited no detectable toxicity in our assays. Interestingly, the deletion of the MtvTA significantly increased the transfer efficiency of pPAD8 from PAD8 to P. aeruginosa strain PAO1. Functional assays revealed that the MtvTA complex negatively regulates plasmid transfer by binding to the promoters of dot/icm system genes. In addition, pPAD8ΔmtvTA attenuated the pathogenicity of the host strain compared to pPAD8, highlighting a regulatory role for MtvTA in virulence. Mechanistically, the MtvTA complex positively regulates the type III and type VI secretion systems and pyocyanin biosynthesis by directly binding to the promoters of exsA and rsmY/rsmZ and indirectly influencing lasI expression, respectively. These findings provide new insights into the regulatory roles of an inactive plasmid-encoded TA system, expanding our understanding of the interplay between plasmids and their bacterial hosts.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11826091/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143414877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elevated reactive oxygen species can drive the alternative lengthening of telomeres pathway in ATRX-null cancers.","authors":"Tomas Goncalves, Siobhan Cunniffe, Tiffany S Ma, Natalie Mattis, Andrew W Rose, Thomas Kent, David R Mole, Helene E B Geiller, Linda van Bijsterveldt, Timothy C Humphrey, Ester M Hammond, Richard J Gibbons, David Clynes, Anna M Rose","doi":"10.1093/nar/gkaf061","DOIUrl":"10.1093/nar/gkaf061","url":null,"abstract":"<p><p>The alternative lengthening of telomeres (ALT) pathway is a telomerase-independent mechanism for immortalization in cancer cells and is commonly activated in low-grade and high-grade glioma, as well as osteosarcoma. The ALT pathway can be activated under various conditions and has often been shown to include mutational loss of ATRX. However, this is insufficient in isolation and so other cellular event must also be implicated. It has been shown that excessive accumulation of DNA:RNA hybrid structures (R-loops) and/or formation of DNA-protein crosslinks (DPCs) can be other important driving factors. The underlying cellular events leading to R-loop and DPC formation in ALT cancer cells to date remain unclear. Here, we demonstrate that excessive cellular reactive oxygen species (ROS) is an important causative factor in the evolution of ALT-telomere maintenance in ATRX-deficient glioma. We identified three sources of elevated ROS in ALT-positive gliomas: co-mutation of SETD2, downregulation of DRG2, and hypoxic tumour microenvironment. We demonstrate that elevated ROS leads to accumulation of R-loops and, crucially, resolution of R-loops by the enzyme RNase H1 prevents ALT pathway activity in cells exposed to elevated ROS. Further, we found a possible causal link between the formation of R-loops and the accumulation of DPCs, in particular, formation of TOP1 complexes covalently linked to DNA (Top1cc). We also demonstrate that elevation of ROS can trigger over-activity of the ALT pathway in osteosarcoma and glioma cell lines, resulting in excessive DNA damage and cell death. This work presents important mechanistic insights into the endogenous origin of excessive R-loops and DPCs in ALT-positive cancers, as well as highlighting potential novel therapeutic approaches in these difficult-to-treat cancer types.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11806356/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143374498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CRISPuRe-seq: pooled screening of barcoded ribonucleoprotein reporters reveals regulation of RNA polymerase III transcription by the integrated stress response via mTOR.","authors":"David T Harris, Calvin H Jan","doi":"10.1093/nar/gkaf062","DOIUrl":"10.1093/nar/gkaf062","url":null,"abstract":"<p><p>Genetic screens using CRISPR (Clustered Regularly Interspaced Palindromic Repeats) provide valuable information about gene function. Nearly all pooled screening technologies rely on the cell to link genotype to phenotype, making it challenging to assay mechanistically informative, biochemically defined phenotypes. Here, we present CRISPuRe-seq (CRISPR PuRification), a novel pooled screening strategy that expands the universe of accessible phenotypes through the purification of ribonucleoprotein complexes that link genotypes to expressed RNA barcodes. While screening for regulators of the integrated stress response (ISR), we serendipitously discovered that the ISR represses transfer RNA (tRNA) production under conditions of reduced protein synthesis. This regulation is mediated through inhibition of mTORC1 and corresponding activation of the RNA polymerase III inhibitor MAF1. These data demonstrate that coherent downregulation of tRNA expression and protein synthesis is achieved through cross-talk between the ISR and mTOR, two master integrators of cell state.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11806354/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143374497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ubiquitin protease Ubp1 cooperates with Ubp10 and Ubp12 to revert lysine-164 PCNA ubiquitylation at replication forks.","authors":"Javier Zamarreño, Sergio Rodríguez, Sofía Muñoz, Avelino Bueno, María P Sacristán","doi":"10.1093/nar/gkaf076","DOIUrl":"10.1093/nar/gkaf076","url":null,"abstract":"<p><p>Proliferating cell nuclear antigen (PCNA) is essential for the faithful duplication of eukaryotic genomes. PCNA also orchestrates events necessary to address threats to genomic integrity, such as the DNA damage tolerance (DDT) response, a mechanism by which eukaryotic cells bypass replication-blocking lesions to maintain replisome stability. DDT is regulated by the ubiquitylation of PCNA and the consequent recruitment of specialized polymerases that ensure replication continuity. We have recently described that the deubiquitylases Ubp10 and Ubp12 modulate DDT events by reverting the ubiquitylation of PCNA in Saccharomyces cerevisiae. This study identifies Ubp1 as a novel PCNA deubiquitylase that cooperates with Ubp10 and Ubp12 in the regulation of DDT during DNA replication. Ubp1, previously known as a cytoplasmic protein, also localizes to the nucleus, where it associates with DNA replication forks. Additionally, Ubp1 interacts with and deubiquitylates PCNA. Here, we provide evidence that Ubp1 collaborates with Ubp10 and Ubp12 to facilitate DNA replication by efficiently reverting PCNAK164 ubiquitylation at replication forks under conditions free from exogenous perturbations. Consequently, the deletion of UBP1, UBP10, and UBP12 leads to persistent ubiquitylation of PCNAK164 and a marked delay in S phase progression.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11833686/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A phosphorylation signal activates genome-wide transcriptional control by BfmR, the global regulator of Acinetobacter resistance and virulence.","authors":"Nicole Raustad, Yunfei Dai, Akira Iinishi, Arpita Mohapatra, Mark W Soo, Everett Hay, Gabrielle M Hernandez, Edward Geisinger","doi":"10.1093/nar/gkaf063","DOIUrl":"https://doi.org/10.1093/nar/gkaf063","url":null,"abstract":"<p><p>The nosocomial pathogen Acinetobacter baumannii is a major threat to human health. The sensor kinase-response regulator system, BfmS-BfmR, is essential to multidrug resistance and virulence in the bacterium and represents a potential antimicrobial target. Important questions remain about how the system controls resistance and pathogenesis. Although BfmR knockout alters expression of >1000 genes, its direct regulon is undefined. Moreover, how phosphorylation controls the regulator is unclear. Here, we address these problems by combining mutagenesis, ChIP-seq, and in vitro phosphorylation to study the functions of phospho-BfmR. We show that phosphorylation is required for BfmR-mediated gene regulation, antibiotic resistance, and sepsis development in vivo. Consistent with activating the protein, phosphorylation induces dimerization and target DNA affinity. Integrated analysis of genome-wide binding and transcriptional profiles of BfmR led to additional key findings: (1) Phosphorylation dramatically expands the number of genomic sites BfmR binds; (2) DNA recognition involves a direct repeat motif widespread across promoters; (3) BfmR directly regulates 303 genes as activator (e.g., capsule, peptidoglycan, and outer membrane biogenesis) or repressor (pilus biogenesis); (4) BfmR controls several non-coding sRNAs. These studies reveal the centrality of a phosphorylation signal in driving A. baumannii disease and disentangle the extensive pathogenic gene-regulatory network under its control.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143458907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elevated reactive oxygen species can drive the alternative lengthening of telomeres pathway in ATRX-null cancers.","authors":"Tomas Goncalves, Siobhan Cunniffe, Tiffany S Ma, Natalie Mattis, Andrew W Rose, Thomas Kent, David R Mole, Helene E B Geiller, Linda van Bijsterveldt, Timothy C Humphrey, Ester M Hammond, Richard J Gibbons, David Clynes, Anna M Rose","doi":"10.1093/nar/gkaf061","DOIUrl":"https://doi.org/10.1093/nar/gkaf061","url":null,"abstract":"<p><p>The alternative lengthening of telomeres (ALT) pathway is a telomerase-independent mechanism for immortalization in cancer cells and is commonly activated in low-grade and high-grade glioma, as well as osteosarcoma. The ALT pathway can be activated under various conditions and has often been shown to include mutational loss of ATRX. However, this is insufficient in isolation and so other cellular event must also be implicated. It has been shown that excessive accumulation of DNA:RNA hybrid structures (R-loops) and/or formation of DNA-protein crosslinks (DPCs) can be other important driving factors. The underlying cellular events leading to R-loop and DPC formation in ALT cancer cells to date remain unclear. Here, we demonstrate that excessive cellular reactive oxygen species (ROS) is an important causative factor in the evolution of ALT-telomere maintenance in ATRX-deficient glioma. We identified three sources of elevated ROS in ALT-positive gliomas: co-mutation of SETD2, downregulation of DRG2, and hypoxic tumour microenvironment. We demonstrate that elevated ROS leads to accumulation of R-loops and, crucially, resolution of R-loops by the enzyme RNase H1 prevents ALT pathway activity in cells exposed to elevated ROS. Further, we found a possible causal link between the formation of R-loops and the accumulation of DPCs, in particular, formation of TOP1 complexes covalently linked to DNA (Top1cc). We also demonstrate that elevation of ROS can trigger over-activity of the ALT pathway in osteosarcoma and glioma cell lines, resulting in excessive DNA damage and cell death. This work presents important mechanistic insights into the endogenous origin of excessive R-loops and DPCs in ALT-positive cancers, as well as highlighting potential novel therapeutic approaches in these difficult-to-treat cancer types.</p>","PeriodicalId":19471,"journal":{"name":"Nucleic Acids Research","volume":"53 4","pages":""},"PeriodicalIF":16.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143458965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}