Regulation of rII and region D transcription in T4 bacteriophage: A sucrose gradient analysis

Abstract The size distributions of RNA from the T4 rII region and the adjacent D region have been determined by a combination of sucrose gradient analysis and hybridization competition. T4 rII RNA is distributed throughout the gradients, and a considerable amount is found in high molecular weight fractions. RNA from region D2 has a much different distribution, being found primarily in low molecular weight fractions. The distribution of D2 RNA is not appreciably different if infection is carried out in the presence of chloramphenicol. These results indicate that rII RNA is frequently part of a transcription unit which is polycistronic and terminates near the beginning of D2. The transcription unit for D2 does not appear to extend into the adjacent gene 52.