FLAGELLIN GENE-TRANSCRIPTION IN BORDETELLA-BRONCHISEPTICA IS REGULATED BY THE BVGAS VIRULENCE CONTROL-SYSTEM
FLAGELLIN GENE-TRANSCRIPTION IN BORDETELLA-BRONCHISEPTICA IS REGULATED BY THE BVGAS VIRULENCE CONTROL-SYSTEM
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DOI：
10.1128/jb.175.11.3468-3479.1993
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发表时间：
1993-06-01
影响因子：
3.2
通讯作者：
MILLER, JF
中科院分区：
文献类型：
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作者：
AKERLEY, BJ;MILLER, JF
bvgAS基因座的产物激活大多数已知的博德特氏菌毒力因子的表达，但也对一类称为vrg基因（bvg-阻遏基因）的基因施加负控制。BvgAS对支气管败血波氏杆菌中鞭毛的产生和运动性表型负调控。在本研究中，克隆并表征了flaA，鞭毛蛋白基因，以促进对该阴性对照途径的研究。内部flaA探针在百日咳博德特氏菌、副百日咳博德特氏菌和鸟博德特氏菌的基因组Southern印迹上检测到杂交序列，尽管B.百日咳和B.副百日咳是不活动。FlaA类似于鼠伤寒沙门氏菌和大肠杆菌的FliC鞭毛蛋白，并且flaA补充了大肠杆菌。coli鞭毛蛋白突变体。染色体flaA基因座的插入失活消除了运动性，通过与野生型基因座互补恢复了运动性。通过北方印迹和引物延伸分析flaA mRNA的产生，表明BvgAS的负调节发生在转录水平。flaA的转录起始位点定位在大肠杆菌中由flaA编码的替代σ因子σ（F）的共有位点附近。coli和革兰氏阳性菌S.鼠伤寒。与fliA类似物在B中的作用一致。支气管败血症，在大肠杆菌中flaA-lacZ融合体转录激活。coli需要flaA，命名为frl.frl的flaA连锁基因座也有效地互补了大肠杆菌鞭毛主调节基因座flhDC中的突变。杆菌我们对B.支气管败血性杆菌提示博德特氏杆菌毒力控制系统通过包括frl基因座和另一σ因子的调控体系介导flaA的转录控制。
The products of the bvgAS locus activate expression of a majority of the known Bordetella virulence factors but also exert negative control over a class of genes called vrg genes (bvg-repressed genes). BvgAS negatively controls the production of flagella and the phenotype of motility in Bordetella bronchiseptica. In this study flaA, the flagellin gene, was cloned and characterized to facilitate studies of this negative control pathway. An internal flaA probe detected hybridizing sequences on genomic Southern blots of Bordetella pertussis, Bordetella parapertussis, and Bordetella avium, although B. pertussis and B. parapertussis are nonmotile. FlaA is similar to the FliC flagellins of Salmonella typhimurium and Escherichia coli, and flaA complemented an E. coli flagellin mutant. Insertional inactivation of the chromosomal flaA locus eliminated motility, which was restored by complementation with the wild-type locus. Analysis of flaA mRNA production by Northern (RNA) blotting and primer extension indicated that negative regulation by BvgAS occurs at the level of transcription. The transcriptional start site of flaA mapped near a consensus site for the alternative sigma factor, sigma(F), encoded by flaA in E. coli and S. typhimurium. Consistent with a role for a fliA analog in B. bronchiseptica, transcriptional activation of a flaA-lacZ fusion in E. coli required flaA and a flaA-linked locus designated frl.frl also efficiently complemented mutations in the flagellar master regulatory locus, flhDC, of E. coli. Our analysis of the motility phenotype of B. bronchiseptica suggests that the Bordetella virulence control system mediates transcriptional control of flaA through a regulatory hierarchy that includes the frl locus and an alternative sigma factor.