Reversal by certain polyanions of an endogenous inhibitor of the vesicular stomatitis virus-associated transcriptase.

The RNA-dependent RNA polymerase associated with vesicular stomatitis virus has been found to be markedly inhibited at high concentrations of virus. This endogenous inhibitor of the virion transcriptase was completely reversed by the action of two negatively charged polyamino acids: poly(L-glutamic acid) and pepsin (EC 3.4.23.1). Two other polyanions, heparin and polyethylene sulfonate, strongly inhibited the activity of the virion transcriptase even at low virus concentrations. Poly (L-glutamic acid) rapidly released the block in transcription of concentrated vesicular stomatitis virus, possibly owing to competition for binding sites of the inhibitor on the virion nucleocapsid transcription complex.