Role of the histone-like nucleoid structuring protein in the regulation of rpoS and RpoS-dependent genes in Vibrio cholerae.
Production of the Zn-metalloprotease hemagglutinin (HA)/protease by Vibrio cholerae has been reported to enhance enterotoxicity in rabbit ileal loops and the reactogenicity of live cholera vaccine candidates. Expression of HA/protease requires the alternate sigma factor sigma(S) (RpoS), encoded by rpoS. The histone-like nucleoid structuring protein (H-NS) has been shown to repress rpoS expression in Escherichia coli. In V. cholerae strains of the classical biotype, H-NS has been reported to silence virulence gene expression. In this study we examined the role of H-NS in the expression of HA/protease and motility in an El Tor biotype strain by constructing a Deltahns mutant. The Deltahns mutant exhibited multiple phenotypes, such as production of cholera toxin in nonpermissive LB medium, reduced resistance to high osmolarity, enhanced resistance to low pH and hydrogen peroxide, and reduced motility. Depletion of H-NS by overexpression of a dominant-negative allele or by deletion of hns resulted in diminished expression of HA/protease. Epistasis analysis of HA/protease expression in Deltahns, DeltarpoS, and Deltahns DeltarpoS mutants, analysis of RpoS reporter fusions, quantitative reverse transcription-PCR measurements, and ectopic expression of RpoS in DeltarpoS and DeltarpoS Deltahns mutants showed that H-NS posttranscriptionally enhances RpoS expression. The Deltahns mutant exhibited a lower degree of motility and lower levels of expression of flaA, flaC, cheR-2, and motX mRNAs than the wild type. Comparison of the mRNA abundances of these genes in wild-type, Deltahns, DeltarpoS, and Deltahns DeltarpoS strains revealed that deletion of rpoS had a more severe negative effect on their expression. Interestingly, deletion of hns in the rpoS background resulted in higher expression levels of flaA, flaC, and motX, suggesting that H-NS represses the expression of these genes in the absence of sigma(S). Finally, we show that the cyclic AMP receptor protein and H-NS act along the same pathway to positively affect RpoS expression.
Silva
Anisia J
AJ
Department of Microbiology, Biochemistry, and Immunology, Morehouse School of Medicine, 720 Westview Dr., SW, Atlanta, GA 30310, USA. asilva-benitez@msm.edu
Sultan
Syed Zafar
SZ
Liang
Weili
W
Benitez
Jorge A
JA
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002633:Chemotaxis; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D016254:Mutagenesis, Insertional; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014734:Vibrio cholerae / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria
J Bacteriol. 2006 Jan;188(2):794-800
16385069
Proc Natl Acad Sci U S A. 1997 Jan 7;94(1):265-70
8990197
J Bacteriol. 2004 Oct;186(19):6374-82
15375117
J Bacteriol. 2006 Oct;188(19):7022-5
16980505
Mol Microbiol. 2001 Jul;41(2):393-407
11489126
J Bacteriol. 1991 Jun;173(11):3311-7
2045361
Plasmid. 1981 Jul;6(1):112-8
7025054
J Bacteriol. 2000 Apr;182(7):2026-32
10715012
J Bacteriol. 1998 Dec;180(23):6117-25
9829919
J Bacteriol. 2002 Mar;184(6):1767-71
11872729
J Bacteriol. 1998 Feb;180(4):773-84
9473029
J Bacteriol. 2001 May;183(9):2746-54
11292792
FEMS Microbiol Lett. 2004 Oct 1;239(1):1-8
15451094
Mol Microbiol. 1995 Sep;17(6):1133-42
8594332
Microbiology (Reading). 2003 Jul;149(Pt 7):1883-1891
12855739
Curr Opin Microbiol. 2002 Feb;5(1):51-5
11834369
FEMS Microbiol Lett. 1990 Mar 1;56(1-2):149-54
2332153
Infect Immun. 1999 Feb;67(2):539-45
9916056
Proc Natl Acad Sci U S A. 1999 May 25;96(11):6439-44
10339606
Microb Pathog. 1996 Aug;21(2):111-23
8844654
Gene. 1987;51(2-3):255-67
3110013
Microb Pathog. 1998 May;24(5):321-6
9600864
Cell. 2002 Aug 9;110(3):303-14
12176318
PLoS Pathog. 2006 Oct;2(10):e109
17054394
Nat Rev Microbiol. 2004 May;2(5):391-400
15100692
Mol Microbiol. 1999 Jul;33(1):8-17
10411719
Infect Immun. 2006 May;74(5):3060-4
16622251
Mol Microbiol. 2002 Jan;43(1):119-34
11849541
Mol Microbiol. 1997 Dec;26(5):1023-34
9426139
J Bacteriol. 2005 Dec;187(24):8403-10
16321945
Clin Microbiol Rev. 1995 Jan;8(1):48-86
7704895
Infect Immun. 1991 Dec;59(12):4310-7
1937792
Mol Microbiol. 2001 Mar;39(6):1595-609
11260476
Infect Immun. 2001 Oct;69(10):6549-53
11553605
EMBO J. 1993 Mar;12(3):1039-46
8458322
Infect Immun. 2005 May;73(5):3018-24
15845509
EMBO J. 1997 Apr 1;16(7):1795-805
9130723
Appl Environ Microbiol. 2006 Nov;72(11):7043-9
16950899
Mol Microbiol. 1997 Apr;24(1):7-17
9140961
J Bacteriol. 1991 Aug;173(15):4717-24
1649820
Curr Opin Microbiol. 2000 Apr;3(2):154-8
10744991
J Bacteriol. 1998 Jan;180(2):303-16
9440520
Microbiology (Reading). 2007 Sep;153(Pt 9):2964-2975
17768239
Cell. 1992 Oct 16;71(2):255-65
1423593
Mol Microbiol. 2001 Apr;40(1):20-36
11298273
Mol Microbiol. 2003 Oct;50(2):427-44
14617169
Infect Immun. 2006 Apr;74(4):2072-9
16552036
Microbiol Immunol. 1986;30(11):1075-83
3543624
Cell Microbiol. 2000 Feb;2(1):11-7
11207559
Infect Immun. 2000 Dec;68(12):6691-6
11083783
Mol Microbiol. 2002 Mar;43(6):1471-91
11952899
J Mol Biol. 2004 Jun 4;339(3):505-14
15147838
Infect Immun. 2000 Nov;68(11):6487-92
11035765
Microbiol Mol Biol Rev. 2002 Sep;66(3):373-95, table of contents
12208995
Mol Microbiol. 2004 Jul;53(1):345-54
15225327
Infect Immun. 2004 Jul;72(7):3961-7
15213140
Proc Natl Acad Sci U S A. 1983 Feb;80(4):1092-5
6341990
J Bacteriol. 2000 Aug;182(15):4295-303
10894740
Gene. 1993 Jan 15;123(1):17-24
8380783
Mol Microbiol. 1999 Nov;34(4):836-49
10564522
Mol Microbiol. 2001 Mar;39(5):1382-94
11251852
Curr Opin Microbiol. 2002 Dec;5(6):591-5
12457703