RNA involvement in T4 DNA synthesis in toluene-treated cells

Abstract

In T4-infected cells made permeable with toluene, pulses with [(alpha-32P deoxyribonucleoside triphosphates demonstrated covalent linkage of RNA to DNA of the Okazaki fragments. Analysis of the transfer of the 32P label to the 2'(3') ribonucleoside monophosphates indicated that the 3'-end of the RNA primer is heterogeneous. The most frequently encountered ribonucleotide was rCMP, but also transfer to rUMP, rAMP and rGMP occurred at different frequencies. In contrast, no heterogeneity was observed for the deoxyribonucleoside at the RNA-DNA junction. Of all the [to-32P] deoxyribonucleoside triphosphates tested, transfer of the 32P label to 2'(3') rNMPs was predominant when [alpha32P] dGTP was the substrate, indicating that the deoxyribonucleoside most frequently encountered at the RNA-DNA linkage is dG. These observations suggest that the starts for the Okazaki fragments may occur at unique sites of the T4 genome.