Automodified Poly(ADP-Ribose) Synthetase Detected in Rat Liver Cells is Selectively Attached to a Nuclear Matrix-Like Structure

Abstract

The Stimulation of poly(ADP-ribose) synthesis in vivo and in vitro appears to be generally accompanied by the automodification of poly(ADP-ribose) synthetase. It has been shown that this reaction is enhanced during recovery of cells from DNA damage (1), in response to the action of tumor promoting phorbol esters (2) and in isolated nuclei supplied with exogenous NAD (3). While there are reasonable doubts about a common molecular mechanism underlying the activation of the synthetase in these different cases (4), we were interested in the question of whether the automodification reaction is involved in the regulation of more than one biological function. Here we present evidence that the automodified poly(ADP-ribose) synthetase isolated from unstimulated normal rat liver exhibits distinct features that are not observed with poly(ADP-ribose) conjugates formed in response to stimulation by alkylating agents.