The bacteriophage T4 middle promoter PuvsX: analysis of regions important for binding of the T4 transcriptional activator MotA and for activation of transcription

Mol Microbiol. 1995 Feb;15(4):649-60. doi: 10.1111/j.1365-2958.1995.tb02374.x.


Bacteriophage T4 middle promoters, which are transcribed using phage-modified host RNA polymerase and the T4 transcriptional activator, MotA, match the host sigma 70 consensus sequence at -10, but they have a different consensus ((t/a)(t/a)TGCTT(t/c)A) (a MotA box) at -30. While the T4 middle promoter PuvsX has these -10 and -30 motifs, it also has matches to the MotA box at -35, -51, -70, and -87. We show that MotA binds to PuvsX DNA, footprinting a region that includes the MotA boxes at -30, -35, and -51. Very high levels of MotA are required for footprinting and gel-shift experiments, and protein-DNA complexes formed in the presence of both phage-modified polymerase and MotA are more resistant to HindIII cleavage than those formed with either protein alone. These results suggest that MotA-DNA interactions may be stabilized by phage-modified polymerase. Sequences between -18 and -38 are absolutely required for MotA activation of transcription, but sequences upstream of -38 are stimulatory, particularly when chloride instead of glutamate is the major anion. Our results dissect PuvsX into a core promoter, downstream of -38, which is required for MotA activation, and an upstream region that enhances transcription especially under conditions less favourable for protein-DNA interactions.

MeSH terms

  • Bacteriophage T4 / genetics*
  • Base Sequence
  • Chlorides / pharmacology
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology*
  • Glutamic Acid / pharmacology
  • Membrane Proteins / genetics
  • Molecular Sequence Data
  • Promoter Regions, Genetic / genetics*
  • RNA Polymerase I / metabolism
  • RNA, Messenger / biosynthesis
  • Transcription Factors / physiology*
  • Transcriptional Activation*
  • Viral Proteins / genetics
  • Viral Proteins / physiology*


  • Chlorides
  • DNA-Binding Proteins
  • Membrane Proteins
  • MotA protein, Enterobacteria phage T4
  • RNA, Messenger
  • Transcription Factors
  • UvsX protein, Enterobacteria phage T4
  • Viral Proteins
  • Glutamic Acid
  • RNA Polymerase I