Actions of human DNA glycosylases on uracil-containing DNA, methylated DNA and their reconstituted chromatins.

Abstract

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.

• Authors: K Ishiwata, A Oikawa
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 563 Issue 2 Pg. 375-84 (Jul 26 1979) ISSN: 0006-3002 [Print] Netherlands
• PMID: 465495 (Publication Type: Journal Article)

Chemical References

• Chromatin
• Uracil
• DNA
• Glycoside Hydrolases

Topics

• Animals
• Cattle
• Cell Line
• Chromatin
• DNA
• Glycoside Hydrolases (metabolism)
• Humans
• Kinetics
• Methylation
• Thymus Gland
• Uracil
• Xeroderma Pigmentosum (enzymology)