Actions of human DNA glycosylases on uracil-containing DNA, methylated DNA and their reconstituted chromatins.
Extracts of human lymphoblastoid cells catalyzed complete release of uracil (Ura) from PBS1 DNA, which contains Ura instead of thymine as a normal component (Ura-DNA), and 3-methyladenine (3-MeAde) from DNA methylated with methyl methanesulfonate (Me-DNA). These two activities, Ura-DNA glycosylase and 3-MeAde-DNA glycosylase, differed in heat stability. Cell extracts released Ura more rapidly and 3-MeAde more slowly from alkali-denatured preparations of Ura- and Me-DNA, respectively, than from native DNA's. On incubation with reconstituted chromatins, prepared from Ura-DNA and Me-DNA, respectively, with calf thymus chromosomal protein by salt gradient dialysis, cell extracts released all the Ura but only about half of the 3-MeAde residues, although both these chromatins were degraded by micrococcal nuclease until about half of the nucleotides became acid soluble. The activities of Ura-DNA and 3-MeAde-DNA glycosylase of xeroderma pigmentosum cells were similar to those of normal cells.
D000818:Animals; D002417:Cattle; D002460:Cell Line; D002843:Chromatin; D004247:DNA; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008745:Methylation; D013950:Thymus Gland; D014498:Uracil; D014983:Xeroderma Pigmentosum / Q000201:enzymology
D002843:Chromatin; D014498:Uracil; D004247:DNA; D006026:Glycoside Hydrolases