@article{89631,
  keywords = {nitrogen, Gene Expression Regulation, Promoter Regions, Genetic, Transcription, Genetic, RNA, Messenger, Escherichia coli Proteins, RNA Polymerase Sigma 54},
  author = {Ammar Zafar and Valerie Carabetta and Mark Mandel and Thomas Silhavy},
  title = {Transcriptional occlusion caused by overlapping promoters},
  abstract = {<p>RpoS (σ(38)) is required for cell survival under stress conditions, but it can inhibit growth if produced inappropriately and, consequently, its production and activity are elaborately regulated. Crl, a transcriptional activator that does not bind DNA, enhances RpoS activity by stimulating the interaction between RpoS and the core polymerase. The crl gene has two overlapping promoters, a housekeeping, RpoD- (σ(70)) dependent promoter, and an RpoN (σ(54)) promoter that is strongly up-regulated under nitrogen limitation. However, transcription from the RpoN promoter prevents transcription from the RpoD promoter, and the RpoN-dependent transcript lacks a ribosome-binding site. Thus, activation of the RpoN promoter produces a long noncoding RNA that silences crl gene expression simply by being made. This elegant and economical mechanism, which allows a near-instantaneous reduction in Crl synthesis without the need for transacting regulatory factors, restrains the activity of RpoS to allow faster growth under nitrogen-limiting conditions.</p>
},
  year = {2014},
  journal = {Proc Natl Acad Sci U S A},
  volume = {111},
  pages = {1557-61},
  month = {01/2014},
  issn = {1091-6490},
  doi = {10.1073/pnas.1323413111},
  language = {eng},
}