PMID- 8756462 OWN - NLM STAT- MEDLINE DCOM- 19960918 LR - 20131121 IS - 0006-2960 (Print) IS - 0006-2960 (Linking) VI - 35 IP - 31 DP - 1996 Aug 6 TI - Repair of cisplatin--DNA adducts by the mammalian excision nuclease. PG - 10004-13 AB - Nucleotide excision repair is one of the many cellular defense mechanisms against the toxic effects of cisplatin. An in vitro excision repair assay employing mammalian cell-free extracts was used to determine that the 1,2-d(ApG) intrastrand cross-link, a prevalent cisplatin-DNA adduct, is excised by the excinuclease from a site-specifically modified oligonucleotide 156 base pairs in length. Repair of the minor interstrand d(G)/d(G) cross-link was not detected by using this system. Proteins containing the high mobility group (HMG) domain DNA-binding motif, in particular, rat HMG1 and a murine testis-specific HMG-domain protein, specifically inhibit excision repair of the intrastrand 1,2-d(GpG) and -d(ApG) cross-links. This effect was also exhibited by a single HMG domain from HMG1. Similar inhibition of repair of a site-specific 1,2-d(GpG) intrastrand cross-link by an HMG-domain protein also occurred in a reconstituted system containing highly purified repair factors. These results indicate that HMG-domain proteins can block excision repair of the major cisplatin-DNA adducts and suggest that such an activity could contribute to the unique sensitivity of certain tumors to the drug. The reconstituted excinuclease was more efficient at excising the 1,3-d(GpTpG) intrastrand adduct than either the 1,2-d(GpG) or d(ApG) intrastrand adducts, in agreement with previous experiments using whole cell extracts [Huang, J. -C., Zamble, D. B., Reardon, J. T., Lippard, S. J., Sancar, A. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 10394-10398]. This result suggests that structural differences among the platinated DNA substrates, and not the presence of unidentified cellular factors, determine the relative excision repair rates of cisplatin-DNA intrastrand cross-links in the whole cell extracts. FAU - Zamble, D B AU - Zamble DB AD - Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139, USA. FAU - Mu, D AU - Mu D FAU - Reardon, J T AU - Reardon JT FAU - Sancar, A AU - Sancar A FAU - Lippard, S J AU - Lippard SJ LA - eng GR - CA34992/CA/NCI NIH HHS/United States GR - GM32833/GM/NIGMS NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - United States TA - Biochemistry JT - Biochemistry JID - 0370623 RN - 0 (DNA Adducts) RN - 0 (High Mobility Group Proteins) RN - 0 (Oligodeoxyribonucleotides) RN - 0 (Recombinant Proteins) RN - 0 (cisplatin-DNA adduct) RN - 97C5T2UQ7J (Cholesterol) RN - EC 3.1.- (Endodeoxyribonucleases) RN - Q20Q21Q62J (Cisplatin) SB - IM MH - Animals MH - Base Sequence MH - Binding Sites MH - Cholesterol/metabolism MH - *Cisplatin MH - *DNA Adducts MH - *DNA Repair MH - Endodeoxyribonucleases/*metabolism MH - HeLa Cells MH - High Mobility Group Proteins/chemistry/metabolism/*pharmacology MH - Humans MH - Kinetics MH - Male MH - Mammals MH - Mice MH - Molecular Sequence Data MH - Oligodeoxyribonucleotides MH - Rats MH - Recombinant Proteins/chemistry/metabolism/pharmacology MH - Substrate Specificity MH - Testis EDAT- 1996/08/06 00:00 MHDA- 1996/08/06 00:01 CRDT- 1996/08/06 00:00 PHST- 1996/08/06 00:00 [pubmed] PHST- 1996/08/06 00:01 [medline] PHST- 1996/08/06 00:00 [entrez] AID - bi960453+ [pii] AID - 10.1021/bi960453+ [doi] PST - ppublish SO - Biochemistry. 1996 Aug 6;35(31):10004-13. doi: 10.1021/bi960453+.