Open AccessTwo DNA sites for M el R in the same orientation are sufficient for optimal M el R ‐dependent repression at the E scherichia coli melR promoter
Author(s) -
Elrobh Mohamed S.,
Webster Christine L.,
Samarasinghe Shivanthi,
Durose Danielle,
Busby Stephen J.W.
Publication year - 2013
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12027
Subject(s) - psychological repression , biology , microbiology and biotechnology , genetics , gene , gene expression
The E scherichia coli melR gene encodes the M el R transcription factor that controls melibiose utilization. Expression of melR is autoregulated by M el R , which represses the melR promoter by binding to a target that overlaps the transcript start. Here, we show that M el R ‐dependent repression of the melR promoter can be enhanced by the presence of a second single DNA site for M el R located up to 250 base pairs upstream. Parallels with A ra C ‐dependent repression at the araC–araBAD regulatory region and the possibility of the M el R ‐dependent repression loop formation are discussed. The results show that M el R bound at two distal loci can cooperate together in transcriptional repression.