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Repressor induced site‐specific binding of HU for transcriptional regulation
Author(s) -
Aki Tsunehiro,
Adhya Sankar
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.12.3666
Subject(s) - promoter , biology , repressor , transcription (linguistics) , psychological repression , footprinting , dna , microbiology and biotechnology , binding site , histone , dna binding protein , nucleoprotein , dna footprinting , transcription factor , genetics , gene , gene expression , linguistics , philosophy
Transcription from two overlapping gal promoters is repressed by Gal repressor binding to bipartite gal operators, O E and O I , which flank the promoters. Concurrent repression of the gal promoters also requires the bacterial histone‐like protein HU which acts as a co‐factor. Footprinting experiments using iron–EDTA‐coupled HU show that HU binding to gal DNA is orientation specific and is specifically dependent upon binding of GalR to both O E and O I . We propose that HU, in concert with GalR, forms a specific nucleoprotein higher order complex containing a DNA loop. This way, HU deforms the promoter to make the latter inactive for transcription initiation while remaining sensitive to inducer. The example of gal repression provides a model for studying how a ‘condensed’ DNA becomes available for transcription.