title: Poly(ADP-ribose): release of template restriction in HeLa cells.
abstract: Evidence is presented to show that ADP-ribosylation of nuclear proteins by poly(ADP-ribose) polymerase enhances template-primer activity of HeLa cell nuclear DNA. We used Escherichia coli DNA polymerase I (EC 2.7.7.7; DNA nucleotidyltransferase) as an exogenous probe of nuclear DNA status. Neither NAD nor free poly(ADP-ribose) acts directly on the bacterial enzyme. The stimulation is specific for formation of ADP-ribosylated proteins and is not a generalized polyanion or nucleotide effect on chromatin. The release of template restriction is proportional to the capacity of a given cell line to synthesize poly(ADP-ribose); both the stimulation and poly(ADP-ribose) formation are coordinately proportional to NAD concentration. Binding studies with DNA polymerase indicate exposure or generation of additional 3'-OH primer sites due to ADP-ribosylation in intact nuclei. With intact cells, there appears a correlation among growth, physiological template restriction, and the above effects of ADP-ribosylation.
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004273:DNA, Neoplasm / Q000096:biosynthesis*; D004926:Escherichia coli / Q000201:enzymology; D006367:HeLa Cells / Q000378:metabolism*; D006801:Humans; D009243:NAD / Q000378:metabolism; D009698:Nucleoproteins / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D011119:Polynucleotides / Q000378:metabolism*; D051381:Rats; D012266:Ribose / Q000378:metabolism*; D013698:Templates, Genetic; D013942:Thymine Nucleotides / Q000378:metabolism; D014316:Tritium
chemical_list: D004273:DNA, Neoplasm; D009698:Nucleoproteins; D009702:Nucleoside Diphosphate Sugars; D011119:Polynucleotides; D013942:Thymine Nucleotides; D009243:NAD; D014316:Tritium; D000244:Adenosine Diphosphate; D012266:Ribose; D004254:DNA Nucleotidyltransferases