The Pso4 mRNA splicing and DNA repair complex interacts with WRN for processing of DNA interstrand cross-links.
DNA interstrand cross-links (ICLs) are perhaps the most formidable lesion encountered by the cellular DNA repair machinery, and the elucidation of the process by which they are removed in eukaryotic cells has proved a daunting task. In particular, the early stages of adduct recognition and uncoupling of the cross-link have remained elusive principally because genetic studies have not been highly revealing. We have developed a biochemical assay in which processing of a DNA substrate containing a site-specific psoralen ICL can be monitored in vitro. Using this assay we have shown previously that the mismatch repair factor MutSbeta, the nucleotide excision repair heterodimer Ercc1-Xpf, and the replication proteins RPA and PCNA are involved in an early stage of psoralen ICL processing. Here, we report the identification of two additional factors required in the ICL repair process, a previously characterized pre-mRNA splicing complex composed of Pso4/Prp19, Cdc5L, Plrg1, and Spf27 (Pso4 complex), and WRN the protein deficient in Werner syndrome. Analysis of the WRN protein indicates that its DNA helicase function, but not its exonuclease activity, is required for ICL processing in vitro. In addition, we show that WRN and the Pso4 complex interact through a direct physical association between WRN and Cdc5L. A putative model for uncoupling of ICLs in mammalian cells is presented.
Zhang
Nianxiang
N
Department of Molecular Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Kaur
Ramandeep
R
Lu
Xiaoyan
X
Shen
Xi
X
Li
Lei
L
Legerski
Randy J
RJ
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D018797:Cell Cycle Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004265:DNA Helicases / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics*; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000502:physiology; D005090:Exodeoxyribonucleases; D005363:Ficusin / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D007158:Immunologic Techniques; D008214:Lymphocytes; D009687:Nuclear Proteins; D012326:RNA Splicing / Q000235:genetics*; D000072260:RNA Splicing Factors; D012333:RNA, Messenger / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000502:physiology; D053484:RecQ Helicases; D000071657:Werner Syndrome Helicase
C508357:CDC5L protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D000072260:RNA Splicing Factors; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D004247:DNA; D005090:Exodeoxyribonucleases; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase; D045643:DNA Repair Enzymes; C417041:PRPF19 protein, human; D005363:Ficusin