Open AccessVitreoscilla hemoglobin promoter is not responsive to nitrosative and oxidative stress in Escherichia coli
Author(s) -
Frey Alexander D.,
Koskenkorva Taija,
Kallio Pauli T.
Publication year - 2003
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 - 10.1016/s0378-1097(03)00434-8
Subject(s) - escherichia coli , chloramphenicol acetyltransferase , biology , heterologous , gene , oxidative phosphorylation , gene expression , oxidative stress , regulation of gene expression , heterologous expression , biochemistry , microbiology and biotechnology , promoter , recombinant dna
The Vitreoscilla hemoglobin gene ( vhb ) is expressed under oxygen‐limited conditions via an FNR‐dependent mechanism. Furthermore, cAMP‐CRP has been implicated in its regulation. Recently, VHb protein has been reported to protect a heterologous host from nitrosative stress. In this study we analyzed the regulation of the Vitreoscilla hemoglobin promoter (P vhb ) in Escherichia coli under nitrosative and oxidative stress conditions. Our results show unambiguously that expression of neither VHb nor chloramphenicol acetyltransferase under the control of P vhb is induced under the experimental conditions used. Thus, a clear discrepancy between in vivo function, i.e. protection against nitrosative stress, and regulation of gene expression is obvious. The regulation of P vhb reported here is in clear contrast to the expression pattern of flavohemoglobins from various microorganisms, which are generally induced by nitrosative stress. However, the length of P vhb is only 146 bp and therefore, we cannot rule out that additional regulatory sequences may be located in the upstream region of P vhb .