Deletion analysis of a bacteriophage T4 late promoter.

We have conducted a BAL 31 unidirectional deletion analysis to determine whether the conserved consensus sequence found upstream of all sequenced phage T4 late genes represents the late T4 promoter or is only part of the promoter. The results confirm those of Elliott and Geiduschek [Cell 36 (1984) 211-219] that no sequences upstream from the consensus sequence are necessary for late transcription activity. In addition, they provide evidence that sequences downstream from the consensus sequence are important. We have also constructed a sequence that differs in several positions from the consensus but which still shows the properties of a late T4 promoter. Finally, we have noticed a remarkable homology between the consensus sequence for late T4 promoters and mitochondrial promoters from Saccharomyces cerevisiae and Kluyveromyces lactis.