Unknown,Transcriptomics,Genomics,Proteomics

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Expression data of Schizosaccharomyces pombe deletions involved in DNA damage response

ABSTRACT: DNA damage response (DDR) plays pivotal roles in maintaining genome integrity and stability. An effective DDR requires the involvement of hundreds of genes that compose a complicated network. To identify novel genes involved in DDR, we screened a genome-wide Schizosaccharomyces pombe (S. pombe) haploid deletion library against six different DNA damage reagents. We identified 52 genes that were actively involved in DDR. Among the 52 genes, 20 genes were linked to DDR for the first time. For a better understanding of DDR genes function, we performed a DNA microarray assay to analyze the gene expression profiles of eight deletions. Cells of wild type and eight deletions involved in DDR were collected during the expontentially growing stage, and were subjected to RNA extraction and hybridization on Affymetrix microarrays. We tried to understand the role of genes in DDR by comparing the expression profiles of deletions with that of wild type.

ORGANISM(S): Schizosaccharomyces pombe

SUBMITTER: Wenjuan Mo

PROVIDER: E-GEOD-40747 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:DNA damage response (DDR) is a complex process, essential for cell survival. Especially deleterious type of DNA damage are DNA double-strand breaks (DSB), which can lead to genomic instability and malignant transformation if not repaired correctly. The central player in DSB detection and repair is the ATM kinase which orchestrates the action of several downstream factors. Despite substantial knowledge of DNA repair processes, still several aspects of DNA damage detection and signaling are not fully understood. Recent studies have suggested that long non-coding RNAs (lncRNAs) are involved in DDR. Here, we aimed to identify lncRNAs induced upon DNA damage in an ATM-dependent manner. 7 mRNAs and 10 lncRNAs were significantly induced 1h after ionizing radiation (IR) in healthy donors, whereas none in AT patients. 447 mRNAs and 149 lncRNAs were induced 8h after IR in the control group, while only 100 mRNAs and 3 lncRNAs in AT patients. Among IR-induced mRNAs, we found several genes with well-known functions in DDR. Gene Set Enrichment Analysis and Gene Ontology revealed delayed induction of key DDR pathways in AT patients compared to controls. The induction and dynamics of selected 9 lncRNAs were confirmed by RT-qPCR at several time-points after IR on a larger cohort. Moreover, inhibition of ATM with a specific inhibitor (KU-60019) proved that those lncRNAs are dependent on ATM. Some of the detected lncRNAs are localized next to protein-coding genes involved in DDR. We observed that induction of lncRNAs after IR preceded changes in expression of adjacent genes. This indicates that IR-induced lncRNAs may regulate the transcription of nearby genes. Subcellular fractionation into chromatin, nuclear, and cytoplasmic fractions revealed that the majority of studied lncRNAs are localized in chromatin, which further suggests their role in regulation of gene expression. In summary, our study revealed several lncRNAs induced by IR in an ATM-dependent manner. Their co-localization and co-expression with genes involved in DDR suggest that those lncRNAs may be important players in cellular response to DNA damage.

Project description:Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle or transcription, and are emerging as promising therapeutic targets in cancer cells. The transcriptional kinase, CDK12, is especially intriguing, as it modulates transcription elongation by phosphorylating the carboxy-terminal domain (CTD) of RNA polymerase (Pol II) with subsequent effects on expression of DNA damage response (DDR) genes. Yet the exact mechanism by which CDK12 regulates this vital process remains unclear. Using the selective inhibitor of CDK12/13, THZ5317 and transient transcriptome sequencing (TT-seq), we sought to capture the dynamic transcriptional changes linked to CDK12 by analyzing the immediate, early effects on nascent RNA production after CDK12 depletion in neuroblastoma (NB) cells. CDK12-induced inhibition resulted in gene length-dependent defects in transcription elongation, leading to a disproportionate loss of 3' reads in long genes. Short transcripts, by contrast, including those of replication-dependent histone genes, underwent 3' UTR extension. The effect on long genes was accompanied by premature cleavage and polyadenylation (PCPA), followed by early termination and loss of gene expression. DDR gene transcripts were the most prominent among those terminated by PCPA. Phosphoproteomic analysis indicated that pre-mRNA processing factors, including those involved in CPA , are direct phospho-targets of CDK12 and that CDK depletion phenocopied their effects on transcription. Importantly, sensitivity to CDK12 inhibition was predicted by a lower proportion of U1 snRNP binding sites compared to polyadenylation sites (PAS) and hence a higher propensity to intronic poly(A) site selection - a characteristic observed in most DDR genes. These results support a model in which CDK12 regulates expression of DDR genes not only by regulating transcription elongation through its effects on Pol II CTD phosphorylation, but also through direct phosphorylation of pre-mRNA processing factors. These mechanistic insights may enable the development of new anti-cancer strategies targeting multiple vulnerable steps in CDK12-dependent regulation of DNA damage repair.

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Expression data of Schizosaccharomyces pombe deletions involved in DNA damage response

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