Regional and temporal control of genetic transcription in phage lambda.

Abstract

Base composition of lambda messenger RNA is correlated with time of transcription. The guanine and cytosine contents are low at early times and high at late times. The differences in composition reflect sites of origin as revealed by annealing tests. Transcription is confined to the right half of the DNA at early times, and later extends to both halves. The purine content of the RNA is high at both times, perhaps owing to transcription of a single-DNA strand. Results of competition experiments suggest that there are at least four categories of lambda messenger, presumably reflecting the existence of several genetic units whose transcription is under separate control.