Antisense transcripts enhanced by camptothecin at divergent CpG-island promoters associated with bursts of topoisomerase I-DNA cleavage complex and R-loop formation
Autor: | Susana Bueno, Stefano G. Manzo, Jessica Marinello, Giovanni Chillemi, Giovanni Capranico |
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Přispěvatelé: | J. Marinello, G. Chillemi, S. Bueno, S. G. Manzo, G. Capranico |
Rok vydání: | 2013 |
Předmět: |
DNA Replication
R-loop non-coding RNA RNA polymerase II Gene Regulation Chromatin and Epigenetics chemistry.chemical_compound Cell Line Tumor Genetics Transcriptional regulation Humans RNA Antisense DNA Cleavage Promoter Regions Genetic NEXT GENERATION SEQUENCING biology DNA replication Promoter DNA Cyclin-Dependent Kinase 9 Molecular biology Antisense RNA DNA Topoisomerases Type I chemistry biology.protein DNA supercoil Camptothecin CpG Islands RNA Polymerase II Topoisomerase I Inhibitors Topoisomerasi I |
Zdroj: | Nucleic Acids Research |
ISSN: | 1362-4962 0305-1048 |
DOI: | 10.1093/nar/gkt778 |
Popis: | DNA Topoisomerase I (Top1) is required to relax DNA supercoils generated by RNA polymerases (RNAPs). Top1 is inhibited with high specificity by camptothecin (CPT), an effective anticancer agent, and by oxidative base damage and ribonucleotides in DNA strands, resulting into Top1-DNA cleavage complexes (Top1ccs). To understand how Top1ccs affect genome stability, we have investigated the global transcriptional response to CPT-induced Top1ccs. Top1ccs trigger an accumulation of antisense RNAPII transcripts specifically at active divergent CpG-island promoters in a replication-independent and Top1-dependent manner. As CPT increases antisense transcript levels in the presence of 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole, a transcription inhibitor, Top1ccs likely impair antisense RNA degradation. Time-course data showed a burst of Top1ccs increased by CPT at promoter sites and along transcribed regions, causing a transient block of RNAPII at the promoter. Moreover, cell immunofluorescence analyses showed that Top1ccs induce a transient increase of R-loops specifically at highly transcribed regions such as nucleoli in a Top1-dependent manner. Thus, a specific and highly dynamic transcriptional response to Top1ccs occurs at divergent active CpG-island promoters, which may include a transient stabilization of R-loops. The results clarify molecular features of a response pathway leading to transcription-dependent genome instability and altered transcription regulation. |
Databáze: | OpenAIRE |
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