title: Isolation and characterization of proteins cross-linked to DNA by the antitumor agent methylene dimethanesulfonate and its hydrolytic product formaldehyde.
abstract: This study attempted to characterize proteins cross-linked to DNA of Yoshida lymphosarcoma cells treated with methylene dimethanesulfonate (MDMS) and its hydrolytic products formaldehyde (HCHO) and methanesulfonic acid (MSA). MDMS and HCHO treatments produced a similar extent and type of DNA-protein cross-linking in Yoshida lymphosarcoma cells. All five major histones (H1, H2a, H2b, H3, and H4) were among the nuclear proteins cross-linked to DNA. Certain discrete differences were also apparent in these studies. MDMS cross-linked proteins of 29 and 48 kDa to DNA that were not observed following HCHO treatment alone, and HCHO cross-linked a 26-kDa protein to DNA that was not observed following MDMS treatment. Because semicarbazide prevented all MDMS-induced DNA-protein cross-linking, HCHO must be the component responsible for this lesion. The 26-kDa protein has been identified as an H4-H2b dimer. The formation of this dimer is particularly sensitive to MSA release on hydrolysis of MDMS because, in the presence of MSA, HCHO preferentially cross-linked an H2a-H2b dimer and a 48-kDa non-histone protein to DNA. Differences in DNA-protein cross-linking between these two agents are therefore proposed to arise from discrete changes in chromatin structure induced directly by MSA release.
authors.affiliation: Laboratory of Molecular Pharmacology, National Cancer Institute, Bethesda, Maryland 20892.
authors.forename: P M
authors.initials: PM
authors.lastname: O'Connor
authors.forename: B W
authors.initials: BW
authors.lastname: Fox
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure*; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins / Q000032:analysis*; D005557:Formaldehyde / Q000494:pharmacology*; D006657:Histones / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008741:Methyl Methanesulfonate / Q000031:analogs & derivatives* / Q000494:pharmacology; D008970:Molecular Weight; D051381:Rats; D012513:Sarcoma, Experimental / Q000032:analysis; D012663:Semicarbazides / Q000494:pharmacology
chemical_list: D002843:Chromatin; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D006657:Histones; D012663:Semicarbazides; C002538:methylene dimethanesulfonate; D005557:Formaldehyde; C010059:carbamylhydrazine; D008741:Methyl Methanesulfonate