Open AccessIdentification of a Repressor of a Truncated Denitrification Pathway in Moraxella catarrhalis
Author(s) -
Wei Wang,
Anthony R. Richardson,
Willm MartensHabbena,
David A. Stahl,
Ferric C. Fang,
Eric J. Hansen
Publication year - 2008
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.01032-08
Subject(s) - biology , mutant , moraxella catarrhalis , microbiology and biotechnology , nitrite reductase , orfs , complementation , nitrite , repressor , open reading frame , gene , gene expression , genetics , peptide sequence , haemophilus influenzae , ecology , nitrate , antibiotics
Growth ofMoraxella catarrhalis in a biofilm resulted in marked upregulation of two open reading frames (ORFs),aniA andnorB , predicted to encode a nitrite reductase and a nitric oxide reductase, respectively (W. Wang, L. Reitzer, D. A. Rasko, M. M. Pearson, R. J. Blick, C. Laurence, and E. J. Hansen, Infect. Immun. 75:4959-4971, 2007). An ORF designatednsrR , which was located betweenaniA andnorB , was shown to encode a predicted transcriptional regulator. Inactivation ofnsrR resulted in increased expression ofaniA andnorB in three differentM. catarrhalis strains, as measured by both DNA microarray analysis and quantitative reverse transcriptase PCR. Provision of a wild-typensrR gene intrans in annsrR mutant resulted in decreased expression of the AniA protein. DNA microarray analysis revealed that two other ORFs (MC ORF 683 and MC ORF 1550) were also consistently upregulated in annsrR mutant. Consumption of both nitrite and nitric oxide occurred more rapidly with cells of annsrR mutant than with wild-type cells. However, growth ofnsrR mutants was completely inhibited by a low level of sodium nitrite. This inhibition of growth by nitrite was significantly reversed by introduction of ananiA mutation into thensrR mutant and was completely reversed by the presence of a wild-typensrR gene intrans . NsrR regulation of the expression ofaniA was sensitive to nitrite, whereas NsrR regulation ofnorB was sensitive to nitric oxide.