RNA Polymerase and T4 Development

On infection of a suitable host bacterium by bacteriophage T4, development of the phage proceeds according to a carefully controlled program which culminates in the lysis of the host and the release of progeny phage. During the initial or early period of development phage proteins necessary for phage-specific DNA synthesis (Cohen, 1963) and for the turnoff of host macromolecular syntheses appear (Hayward and Green, 1965; Nomura et al., 1966; Ennis and Cohen, 1968; Adesnik and Levinthal, 1970). Shortly after phage DNA replication has commenced the pattern of phage protein synthesis changes dramatically so that the manufacture of structural components of the viral particle now predominates (Levinthal et al., 1967). These changes in protein synthesis are correlated with and are probably a direct consequence of similar changes in the pattern of transcription.