Early Transcription in T4-Infected Cells

The sequential appearance of early T4 messenger RNA (mRNA) species has been well documented (Salser, Bolle, and Epstein, 1970; Milanesi, Brody, and Geiduschek, 1969; Grasso and Buchanan, 1969). Immediately after infection, a subset of early messengers is made and, as the early period unfolds, progressively more early cistrons are transcribed, until between 4 and 5 min after infection (at 30°C), all early genes are being transcribed (Bolle, Epstein, Salser, and Geiduschek, 1968a). If, however, infection is carried out in the presence of chloramphenicol (CAM), transcription appears to be restricted to the subset of early RNA which is normally present by 1.5 min after infection (Salser, Bolle, and Epstein, 1970). Other conditions of protein synthesis inhibition also limit RNA synthesis to this subset (Grasso and Buchanan, 1969; Ennis and Cohen, 1968). These RNA species are defined as immediate early (IE) RNA; the rest of the RNA species which appear between 1.5...