Characterization of a factor that can prevent random transcription of cloned rDNA and its probable relationship to poly(ADP-ribose) polymerase.
A factor which eliminated nonspecific transcription of cloned rat rDNA was extensively purified from rat mammary adenocarcinoma ascites cells by successive fractionations on DEAE-Sephadex and heparin-Sepharose columns. The fractions containing RNA polymerase I (HS-B) and fractions eluting thereafter (HS-C) from the heparin-Sepharose column were pooled separately. Addition of HS-C to HS-B prevented random transcription of rDNA and yielded an accurate rDNA transcript with negligible non-specific transcription. The factor was essentially homogeneous and corresponded to Poly(ADP-ribose) polymerase with respect to molecular weight, dependence on DNA for its activity and its ability to undergo auto ADP-ribosylation. The total amount of protein in the transcription assay was approximately 2 micrograms, which indicates a high degree of purity of all the factors required for specific transcription of rDNA.
Kurl
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Jacob
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D000230:Adenocarcinoma / Q000235:genetics; D000818:Animals; D003001:Cloning, Molecular; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004275:DNA, Ribosomal / Q000235:genetics* / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000235:genetics; D008970:Molecular Weight; D009244:NAD+ Nucleosidase / Q000502:physiology*; D011065:Poly(ADP-ribose) Polymerases / Q000502:physiology*; D051381:Rats; D013347:Subcellular Fractions / Q000502:physiology; D014157:Transcription Factors / Q000302:isolation & purification* / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D004275:DNA, Ribosomal; D014157:Transcription Factors; D011065:Poly(ADP-ribose) Polymerases; D009244:NAD+ Nucleosidase; D004264:DNA Topoisomerases, Type I