Open AccessConstitutive expression of Pasteurella multocida toxin
Author(s) -
Hoskins Isobel C.,
Lax Alistair J.
Publication year - 1996
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 - 10.1111/j.1574-6968.1996.tb08383.x
Subject(s) - frameshift mutation , repressor , mutant , biology , pasteurella multocida , escherichia coli , gene , microbiology and biotechnology , gene expression , psychological repression , regulation of gene expression , genetics , mutation , bacteria
The expression of the Pasteurella multocida toxin (PMT) gene toxA was investigated. Growth in vitro at 30 °C or added iron caused less than 4‐fold repression of toxA expression. The putative repressor TxaR was expressed in Escherichia coli but deletion and frameshift mutations abolishing TxaR production had no effect on toxA expression. Naturally occurring nontoxigenic mutants which contained the toxA gene had no large rearrangements near toxA or changes in toxA promoter structure. Thus PMT is constitutively expressed and is only regulated in a minor way.