title: Expression of FLJB:Z66 on a Linear Plasmid of Salmonella Enterica Serovar Typhi is Dependent on FLIA and FLHDC and Regulated By OMPR.
abstract: Salmonella enterica serovar Typhi z66-positive strains have two different flagellin genes, fliC:d/j and fljB:z66, located on the chromosome and on a linear plasmid, respectively. To investigate the mechanism underlying the expressional regulation of fljB:z66, gene deletion mutants of the regulators FliA, FlhDC, and OmpR were constructed in this study. The expression levels of fliC and fljB:z66 were analyzed by qRT-PCR in the wild-type strain and mutants at high and low osmolarity. The results show that the expression levels of both fljB:z66 and fliC were greatly reduced in fliA and flhDC mutants under both high and low osmotic conditions. In the ompR mutant, the expression levels of fljB:z66, fliC, fliA, and flhD were increased at low osmotic conditions. SDS-PAGE and western blotting analysis of the secreted proteins revealed that the FljB:z66 was almost absent in the fliA and flhDC mutants at both high and low osmolarity. In the wild-type strain, the fljB:z66 was more highly expressed under high-osmolarity conditions than under low-osmolarity conditions. However, this difference in expression disappeared in the ompR mutant. Translational expression assay of FljB:z66 showed that the FljB:z66 expression was decreased in ompR mutant at both low and high osmolarity. These results suggest that the expression of fljB:z66 in S. enterica serovar Typhi is dependent on FliA and FlihDC, and OmpR can regulate the expression and secretion of FljB:z66 in different osmolarity.
authors.affiliation: Department of Biochemistry and Molecular Biology, Jiangsu University School of Medical Technology , Jiangsu Zhenjiang, 212013 , China .
authors.forename: Shungao
authors.initials: S
authors.lastname: Xu
authors.forename: Xin
authors.initials: X
authors.lastname: Zou
authors.forename: Xiumei
authors.initials: X
authors.lastname: Sheng
authors.forename: Haifang
authors.initials: H
authors.lastname: Zhang
authors.forename: Lingxiang
authors.initials: L
authors.lastname: Mao
authors.forename: Hong
authors.initials: H
authors.lastname: Du
authors.forename: Huaxi
authors.initials: H
authors.lastname: Xu
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Huang
keywords: Salmonella enterica serovar Typhi; flhDC; fliA; fljB:z66; ompR.
references.citation: Infect Immun. 1992 Jun;60(6):2475-80
references.pmid: 1587617
references.citation: J Bacteriol. 1990 Feb;172(2):741-7
references.pmid: 2404955
references.citation: Microbiol Immunol. 2009 Apr;53(4):191-7
references.pmid: 19341422
references.citation: Mol Microbiol. 1998 Aug;29(3):835-50
references.pmid: 9723922
references.citation: Ann Microbiol (Paris). 1981 May-Jun;132(3):331-4
references.pmid: 7294611
references.citation: FEMS Microbiol Lett. 2004 May 15;234(2):239-46
references.pmid: 15135528
references.citation: Mol Microbiol. 2007 Dec;66(5):1207-18
references.pmid: 17976161
references.citation: J Gen Microbiol. 1984 Feb;130(2):255-65
references.pmid: 6374019
references.citation: FEMS Microbiol Lett. 1998 Apr 1;161(1):201-8
references.pmid: 9561749
references.citation: Microbiol Immunol. 2001;45(2):149-58
references.pmid: 11293481
references.citation: J Bacteriol. 2003 Sep;185(17):5290-4
references.pmid: 12923104
references.citation: Epidemiol Infect. 1988 Oct;101(2):311-4
references.pmid: 3181315
references.citation: Infect Immun. 2001 May;69(5):3021-30
references.pmid: 11292720
references.citation: Mol Gen Genet. 1997 Apr 28;254(4):440-8
references.pmid: 9180698
references.citation: J Mol Biol. 1992 Jan 5;223(1):171-84
references.pmid: 1370543
references.citation: New Microbiol. 2008 Apr;31(2):241-7
references.pmid: 18623990
references.citation: PLoS Pathog. 2007 May 11;3(5):e59
references.pmid: 17500588
references.citation: J Mol Biol. 1962 Apr;4:227-38
references.pmid: 14455344
references.citation: Infect Immun. 2001 Sep;69(9):5619-25
references.pmid: 11500437
references.citation: Mol Microbiol. 1996 Jan;19(1):1-5
references.pmid: 8821931
references.citation: Cell Microbiol. 2008 Jan;10(1):247-61
references.pmid: 17725646
references.citation: PLoS One. 2009;4(3):e4809
references.pmid: 19277208
references.citation: Infect Immun. 1994 Sep;62(9):3984-93
references.pmid: 8063417
references.citation: J Bacteriol. 1995 Aug;177(16):4696-702
references.pmid: 7642497
references.citation: Mol Gen Genet. 1987 Apr;207(1):120-9
references.pmid: 3037276