In Vitro Replication of Bacteriophage GA RNA. Involvement of Host Factor(s) in GA RNA Replication1

Abstract

A certain factor(s) derived from Escherichia coli was found to extensively stimulate RNA synthesis by the RNA replicase of phage GA. This factor(s), named GA-HF (host factor(s) for GA RNA replication), was partially purified from an uninfected cell extract and characterized. In the presence of GA-HF, GA replicase synthesized 50–100 times more RNA than was synthesized in its absence, and was capable of synthesizing both the viral strand as well as its complementary strand. This factors) could not be replaced by HFI, which is necessary for the replication of Qβ RNA by Qβ replicase. In the presence of GA-HF, the GA RNA replication system has a characteristic template specificity. Group I and II phage RNAs, but none of the Group III and IV phage RNAs, showed template activity.