Open AccessMultiple pathways to bypass the enhancer requirement of sigma 54 RNA polymerase: Roles for DNA and protein determinants
Author(s) -
Jonathan T. Wang,
Adeela Syed,
Jay D. Gralla
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.18.9538
Subject(s) - enhancer , sigma factor , polymerase , rna polymerase , biology , transcription (linguistics) , dna , microbiology and biotechnology , rna , genetics , transcription factor , gene , linguistics , philosophy
Sigma 54 is a required factor for bacterial RNA polymerase to respond to enhancers and directs a mechanism that is a hybrid between bacterial and eukaryotic transcription. Three pathways were found that bypass the enhancer requirementin vitro . These rely on either deletion of the sigma 54 N terminus or destruction of the DNA consensus −12 promoter recognition element or altering solution conditions to favor transient DNA melting. Each of these allows unstable heparin-sensitive pre-initiation complexes to form that can be driven to transcribe in the absence of both enhancer protein and ATP β–γ hydrolysis. These disparate pathways are proposed to have a common basis in that multiple N-terminal contacts may mediate the interactions between the polymerase and the DNA region where melting originates. The results raise possibilities for common features of open complex formation by different RNA polymerases.