The effect of IHF on sigmaS selectivity of the phoA and pst promoters of Escherichia coli.
The pst operon, a member of the PHO regulon of Escherichia coli, encodes a high-affinity phosphate transport system whose expression is induced when the cells enter a phase of phosphate starvation. The expression of pst is stimulated by the integration host factor (IHF). Transcription of the PHO regulon genes is initiated by the RNA polymerase complexed with sigma (D) (Esigma (D)). Owing to a cytosine residue at position -13 of the pst promoter its transcription can also be initiated by Esigma (S). Here, we show that inactivation of IHF in vivo abolishes the sigma (S)-dependent transcription initiation of the pst operon, indicating that both -13C residue and IHF are required to confer on pst the ability to be transcribed by Esigma (S). Introduction of a -13C residue in the promoter region of phoA, another PHO regulon gene that is not directly affected by IHF, did not affect its exclusive transcription initiation by Esigma (D).
Taschner
Natalia Pasternak
NP
Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, CEP 05508-900, São Paulo, Brazil.
Yagil
Ezra
E
Spira
Beny
B
D000469:Alkaline Phosphatase / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D034982:Integration Host Factors / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009876:Operon; D010710:Phosphates / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D018085:Regulon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D034982:Integration Host Factors; D010710:Phosphates; D012808:Sigma Factor; C440502:integration host factor, E coli; C069567:sigma factor KatF protein, Bacteria; D000469:Alkaline Phosphatase