Sequence of a gene encoding a putative primary sigma factor from Borrelia burgdorferi strain B31

Tsai, Ching-Ping; Pan, Ming

doi:10.1016/0378-1119(95)00760-1

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The distinct —35 region could be related to modulation of transcription, as this region binds factors which influence transcriptional expression (Ishihama, 1992). Along these lines, a B. burgdorferi gene encoding a σ 70 -like factor has been identified and sequenced (Tsai & Pan, 1996). Analysis of this gene indicated that the —10 binding region was well conserved when compared to that of other bacteria, whereas the —35 binding region was less conserved (Tsai & Pan, 1996).…”

Section: Resultsmentioning

confidence: 99%

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The flgK motility operon of Borrelia burgdorferi is initiated by a s70-like promoter

Old

Isabelle

et al. 1997

Microbiology

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A cluster of flagellar genes of Borrelia burgdorferi was identified and sequenced. This cluster comprises an operon, designated the flgK operon, which is initiated by a s70-like promoter. The flgK operon consists of flbF (function unknown), flgK (encoding HAP1), flgL (encoding HAP3) and orfX (function unknown), and maps at 185 kb on the chromosome. In other bacteria, the hook-associated proteins HAP1 and HAP3 connect the flagellar filament to the hook and are required for the last stage of flagellar assembly. Reverse transcriptase-PCR analysis indicated that flbF through to orfX are transcribed as a single mRNA, and primer extension analysis revealed that transcription of the flgK operon is initiated by a s70-like promoter upstream of flbF. Subcloning the flgK promoter element into a promoter probe cat vector revealed that the flgK promoter element had strong activity in both Escherichia coli and Salmonella typhimurium. In addition, when this construct was transformed into a fliA mutant of S. typhimurium which lacked a functional flagellar-specific s28factor, the flgK promoter was still functional. Based on these results, the promoter element of the flagellin gene (fla, hereafter referred to as flaB) was re-examined. flaB encodes the flagellar filament protein, and a sgp33-34-like promoter has been reported to be involved in the transcription of this gene. A transcriptional start point was found 1 bp downstream of the reported start site. The sequence around -10 and -35 are consistent with the presence of a s70-like promoter in addition to the putative sgp33-34-like promoter for flaB. In contrast to the flgK promoter element, no activity was detected after subcloning a flaB promoter element into the promoter probe cat vector. Because a s70-like promoter rather than a unique flagellar sigma factor is involved in the later stage of flagellar assembly, the regulation of B. burgdorferi flagellar genes is evidently different from that of other bacteria.

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Section: Resultsmentioning

confidence: 99%

“…Along these lines, a B. burgdorferi gene encoding a σ 70 -like factor has been identified and sequenced (Tsai & Pan, 1996). Analysis of this gene indicated that the —10 binding region was well conserved when compared to that of other bacteria, whereas the —35 binding region was less conserved (Tsai & Pan, 1996).…”

Section: Resultsmentioning

confidence: 99%

The flgK motility operon of Borrelia burgdorferi is initiated by a s70-like promoter

Old

Isabelle

et al. 1997

Microbiology

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“…The expression of these genes does not appear to be the result of a genomic rearrangement, as seen in other Borrelia species, such as Borrelia hermsii (18), but rather is regulated at the level of transcription. The cloning of a putative rpoD gene from B. burgdorferi suggests that the mechanisms of transcriptional regulation in B. burgdorferi may be similar to mechanisms of transcriptional regulation of E. coli 70 promoters (28). A recent survey of 132 E. coli 70 promoters concluded that approximately 49% of the promoters are controlled by a single repressor, whereas 25% are controlled by a single activator (10).…”

Section: Discussionmentioning

confidence: 99%

Cell-density-dependent expression of Borrelia burgdorferi lipoproteins in vitro

et al. 1997

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Previously, we had identified non-OspA-OspB surface proteins of Borrelia burgdorferi that are targeted by the antibody-dependent complement-mediated killing mechanism. Here we demonstrate by Western blotting that one of these proteins, P35, is upregulated at the onset of stationary phase in vitro. Northern analysis revealed that the upregulation of P35 is at the level of transcription. In addition, the expression of an open reading frame (ORF) located downstream of the p35 gene was found to be regulated in the same fashion as that of P35. This ORF encodes a 7.5-kDa lipoprotein. The transcriptional start sites for both of these genes were determined, to aid in the identification of the putative promoter regions. Additional sequencing of the 5 flanking region of the p35 gene revealed a region of dyad symmetry 52 bp upstream of the transcription start site. Southern analysis demonstrated that the expression of these genes was not due to a cell-density-dependent rearrangement in the genome of B. burgdorferi. These findings provide an in vitro model for studying mechanisms of gene regulation in B. burgdorferi.

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Borrelia burgdorferi–Traveling incognito?

Fikrig

Narasimhan

2006

Microbes and Infection

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Sequence of a gene encoding a putative primary sigma factor from Borrelia burgdorferi strain B31

Cited by 4 publications

References 6 publications

The flgK motility operon of Borrelia burgdorferi is initiated by a s70-like promoter

The flgK motility operon of Borrelia burgdorferi is initiated by a s70-like promoter

Cell-density-dependent expression of Borrelia burgdorferi lipoproteins in vitro

Borrelia burgdorferi–Traveling incognito?

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