Indest K J, Ramamoorthy R, Solé M, Gilmore R D, Johnson B J, Philipp M T
Department of Parasitology, Tulane Regional Primate Research Center, Tulane University Medical Center, Covington, Louisiana, USA.
Infect Immun. 1997 Apr;65(4):1165-71. doi: 10.1128/iai.65.4.1165-1171.1997.
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.
此前，我们已鉴定出伯氏疏螺旋体的非OspA - OspB表面蛋白，这些蛋白是抗体依赖性补体介导的杀伤机制的作用靶点。在此，我们通过蛋白质印迹法证明，这些蛋白之一P35在体外稳定期开始时表达上调。Northern分析显示，P35的上调发生在转录水平。此外，发现位于p35基因下游的一个开放阅读框（ORF）的表达与P35的表达调控方式相同。该ORF编码一种7.5 kDa的脂蛋白。确定了这两个基因的转录起始位点，以帮助鉴定推定的启动子区域。对p35基因5'侧翼区域的进一步测序揭示了转录起始位点上游52 bp处的一个二元对称区域。Southern分析表明，这些基因的表达并非由于伯氏疏螺旋体基因组中细胞密度依赖性重排所致。这些发现为研究伯氏疏螺旋体基因调控机制提供了一个体外模型。
