Open AccessTopoisomerase I suppresses genomic instability by preventing interference between replication and transcription
Author(s) -
Sandie Tuduri,
Laure Crabbé,
Chiara Conti,
Hélène Tourrière,
Heidi Holtgreve-Grez,
Anna Jauch,
Véronique Pantesco,
John De Vos,
Aubin Thomas,
Charles Theillet,
Yves Pommier,
Jamal Tazi,
Arnaud Coquelle,
Philippe Pasero
Publication year - 2009
Publication title -
nature cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 11.38
H-Index - 369
eISSN - 1476-4679
pISSN - 1465-7392
DOI - 10.1038/ncb1984
Subject(s) - genome instability , biology , eukaryotic dna replication , dna re replication , origin recognition complex , dna replication , microbiology and biotechnology , control of chromosome duplication , topoisomerase , replication factor c , transcription (linguistics) , dna replication factor cdt1 , genetics , dna , dna damage , linguistics , philosophy
Topoisomerase I (Top1) is a key enzyme in functioning at the interface between DNA replication, transcription and mRNA maturation. Here, we show that Top1 suppresses genomic instability in mammalian cells by preventing a conflict between transcription and DNA replication. Using DNA combing and ChIP (chromatin immunoprecipitation)-on-chip, we found that Top1-deficient cells accumulate stalled replication forks and chromosome breaks in S phase, and that breaks occur preferentially at gene-rich regions of the genome. Notably, these phenotypes were suppressed by preventing the formation of RNA-DNA hybrids (R-loops) during transcription. Moreover, these defects could be mimicked by depletion of the splicing factor ASF/SF2 (alternative splicing factor/splicing factor 2), which interacts functionally with Top1. Taken together, these data indicate that Top1 prevents replication fork collapse by suppressing the formation of R-loops in an ASF/SF2-dependent manner. We propose that interference between replication and transcription represents a major source of spontaneous replication stress, which could drive genomic instability during the early stages of tumorigenesis.