hMutSbeta is required for the recognition and uncoupling of psoralen interstrand cross-links in vitro.
The removal of interstrand cross-links (ICLs) from DNA in higher eucaryotes is not well understood. Here, we show that processing of psoralen ICLs in mammalian cell extracts is dependent upon the mismatch repair complex hMutSbeta but is not dependent upon the hMutSalpha complex or hMlh1. The processing of psoralen ICLs is also dependent upon the nucleotide excision repair proteins Ercc1 and Xpf but not upon other components of the excision stage of this pathway or upon Fanconi anemia proteins. Products formed during the in vitro reaction indicated that the ICL has been removed or uncoupled from the cross-linked substrate in the mammalian cell extracts. Finally, the hMutSbeta complex is shown to specifically bind to psoralen ICLs, and this binding is stimulated by the addition of PCNA. Thus, a novel pathway for processing ICLs has been identified in mammalian cells which involves components of the mismatch repair and nucleotide excision repair pathways.
Zhang
Nianxiang
N
Department of Molecular Genetics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Lu
Xiaoyan
X
Zhang
Xiaoshan
X
Peterson
Carolyn A
CA
Legerski
Randy J
RJ
D000478:Alkylation; D020137:Base Pair Mismatch / Q000235:genetics; D018797:Cell Cycle Proteins; D002457:Cell Extracts; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004720:Endonucleases; D051856:Fanconi Anemia Complementation Group Proteins; D005363:Ficusin / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D021122:Protein Subunits; D011506:Proteins / Q000378:metabolism*
D018797:Cell Cycle Proteins; D002457:Cell Extracts; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D051856:Fanconi Anemia Complementation Group Proteins; C409221:MSH4 protein, human; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D021122:Protein Subunits; D011506:Proteins; D004247:DNA; C071447:ERCC1 protein, human; D004720:Endonucleases; D005363:Ficusin