An N-terminal mutation in the bacteriophage T4 motA gene yields a protein that binds DNA but is defective for activation of transcription

作者：Gerber JS; Hinton DM

来源：Journal of Bacteriology, 1996, 178(21): 6133-6139.

The bacteriophage T4 MotA protein is a transcriptional activator of T4-modified host RNA polymerase and is required for activation of the middle class of T4 promoters, MotA alone binds to the -30 region of T4 middle promoters, a region that contains the MotA box consensus sequence [(t/a)(t/a)TGCTT(t/c)A], We report the isolation and characterization of a protein designated Mot21, in which the first 8 codons of the wild-type motA sequence have been replaced with 11 different codons, In gel retardation assays, Mot21 and MotA bind DNA containing the T4 middle promoter P-uvsX similarly, and the proteins yield similar footprints on P-uvsX. However, Metal is severely defective in the activation of transcription, On native protein gels, a new protein species is seen after incubation of the sigma(70) subunit of RNA polymerase and wild-type MotA protein, suggesting a direct protein-protein contact between MotA and sigma(70), Mot21 fails to form this complex, suggesting that this interaction is necessary for transcriptional activation and that the Mot21 defect arises because Mot21 cannot form this contact like the wild-type activator.

• 出版日期1996-11