Thomassin H, Martins de Sa C, Scherrer K, Maniez C, Mandel P. Cytoplasmic poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase in AEV-transformed chicken erythroblasts.
Mol Biol Rep 1988;
13:35-44. [PMID:
2843754 DOI:
10.1007/bf00805637]
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Abstract
Poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase activities were both investigated in chicken erythroblasts transformed by Avian Erythroblastosis Virus. Respectively 21% and 58% of these activities were found to be present in the post-mitochondrial supernatant (PMS). Fractionation of the PMS on sucrose gradients and poly(A+) mRNA detection by hybridization to [3H] poly(U) show that cytoplasmic poly(ADP-ribose) polymerase is exclusively localized in free mRNP. The glycohydrolase activity sedimented mostly in the 6 S region but 1/3 of the activity was in the free mRNP zone. Seven poly(ADP-ribose) protein acceptors were identified in the PMS in the Mr 21,000-120,000 range. The Mr 120,000 protein corresponds to automodified poly(ADP-ribose) polymerase. A Mr 21,000 protein acceptor is abundant in PMS and a Mr 34,000 is exclusively associated with ribosomes and ribosomal subunits. The existence of both poly(ADP-ribose) polymerase and glycohydrolase activities in free mRNP argues in favour of a role of poly(ADP-ribosylation) in mRNP metabolism. A possible involvement of this post translational modification in the mechanisms of repression-derepression of mRNA is discussed.
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