A majority of <i>Rhodobacter sphaeroides</i> promoters lack a crucial RNA polymerase recognition feature, enabling coordinated transcription activation
Kemardo K. Henry, Wilma Ross, Kevin S. Myers, Kimberly C. Lemmer, Jessica M. Vera, Robert Landick, Timothy J. Donohue, Richard L. Gourse
Abstract
Significance Bacterial promoters are often predicted by similarity to the Escherichia coli −10 and −35 consensus elements. Although these elements are highly conserved in diverse bacterial phyla, only 30 to 43% of promoters we analyzed from Rhodobacter sphaeroides and two other α-proteobacteria contained −7T, a base in the −10 element present in 90 to 99% of promoters from non–α-proteobacteria. Expression from 15 of 16 R. sphaeroides promoters tested in vitro that lacked −7T was very weak, but we identified an essential transcription factor, CarD, that activated all 15 of these promoters. We suggest that promoters lacking a critical base in a consensus element can shape the transcriptome by coordinating expression of large numbers of genes by a single transcription factor.