Accueil > Publications > Recherche par années > Années 2000 > 2007

Nagarajavel, V ; Madhusudan, S ; Dole, S ; Rahmouni, AR ; Schnetz, K

Repression by binding of H-NS within the transcription unit

Journal of Biological Chemistry 282 23622-23630

par Administrateur - publié le

Abstract :

H-NS inhibits transcription by forming repressing nucleoprotein complexes next to promoters. We investigated repression by binding of H-NS within the transcription unit using the bgl and proU operons. Repression of both operons requires a downstream regulatory element (DRE) in addition to an upstream element (URE). In bgl, H-NS binds to a region located between 600 to 700 bp downstream of the transcription start site, whereas in proU the DRE extends up to position +270. We show that binding of H-NS to the bgl-DRE inhibits transcription initiation at a step before open complex formation, as shown before for proU. This was shown by determining the occupancy of the bgl transcription unit by RNA polymerases, expression analysis of bgl and proU reporter constructs, and chloroacetaldehyde footprinting of RNA polymerase promoter complexes.