The process of infection with bacteriophage phiX174, XXII. Synthesis of progeny single-stranded DNA

In a previous article,(1) it was demonstrated that of the labeled thymidine incorporated into the replicative form (RF) of phiX-DNA during the period of RF replication (3-12 or 15 min after infection), approximately half was transferred to virus during the subsequent period of single-strand DNA synthesis, while half remained in RF molecules. In this paper experiments are presented which permit a definition of the label remaining in the RF and which clarify the role of the RF in the synthesis of the progeny single-stranded DNA

The process of infection with bacteriophage phiX174, XXI. Replication and fate of the replicative form

Previous publications have described the formation of a double-stranded DNA intermediate(1) (replicative form, RF) during the replication of bacteriophage phiX174, the semiconservative replication at a bacterial "site"(2) of that RF containing the parental DNA strand,(3,4) and the persistence of the parental DNA strand at the site, accompanied by the release of the daughter RF.(5) The nascent RF molecules first appear as RFII,(6,7) and are rapidly converted to RFI. This paper considers the structure of the nascent RF molecules in more detail and inquires into the fate of the daughter RF molecules during the subsequent period of progeny single-strand DNA formation. A succeeding paper(8) will consider the process of formation of the progeny single-strands

The process of infection with bacteriophage phiX174, XXX. Replication of double-stranded phiX DNA

Intermediates involved in the replication of double-stranded phiX174 RF DNA have been identified and partially characterized. Analysis of pulse-labeled RF DNA suggests that the synthesis of progeny RF molecules involves, in part, the addition of nucleotides to linear complementary strands on a circular parental strand as template, so as to produce intermediate DNA strands of greater than viral length. Electron microscopy reveals DNA rings with "tails" and "double rings," which could be the intermediate structures. A model is postulated for the replication process