Enzymatic initiation of DNA synthesis by yeast DNA polymerases.

Abstract

Partially purified yeast [Saccharomyces cerevisiae] RNA polymerases (RNA nucleotidyltransferases) initiate DNA synthesis by yeast DNA polymerase (DNA nucleotidyltransferase)I and to a lesser extent yeast DNA polymerase II in the replication of single-stranded DNA. The enzymatic initiation of DNA synthesis on phage fd DNA template occurs with dNTP [deoxynucleoside triphosphates] alone and is further stimulated by the presence of r[ribosomal]NTP in DNA polymerase I reactions. The presence of rNTP has no effect on the RNA polymerase initiation of the DNA polymerase II reaction. RNA polymerases I and III are more efficient in initiation of DNA synthesis than RNA polymerase II. Analyses of the products of fd DNA replication show noncovalent linkage between the newly synthesized DNA and the template DNA, and covalent linkage between the newly synthesized RNA and DNA.