FimR and FimS: Biofilm Formation and Gene Expression in Porphyromonas gingivalis
FimR and FimS: Biofilm Formation and Gene Expression in Porphyromonas gingivalis
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DOI：
10.1128/jb.01211-09
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发表时间：
2010-03-01
影响因子：
3.2
通讯作者：
Reynolds, Eric
中科院分区：
文献类型：
--
作者：
Lo, Alvin;Seers, Christine;Reynolds, Eric
牙龈卟啉单胞菌（Porphyromonas gingivalis）是一种晚期定植于龈下牙菌斑生物膜的细菌，与牙周炎有关。预计牙龈卟啉单胞菌的两个基因fimR和fimS编码一个双组分信号传导系统，该系统包括反应调节因子（FimR）和传感器组氨酸激酶（FimS）。在这项研究中，我们表明，fimS和fimR，虽然连续的基因组，是不是操纵子的一部分。我们灭活了无菌毛菌株W50和有菌毛菌株ATCC 33277中的fimR和fimS，并证明了两种突变体形成的生物膜显著少于其各自的野生型菌株。定量逆转录-实时PCR显示，在ATCC 33277菌株的fimS和fimR突变体中，菌毛化基因的表达均降低。在两种菌株中，突变对牙龈卟啉单胞菌的生长速率或对过氧化氢的反应或在pH 9、41 ℃或低氯化血红素可用性下的生长没有影响。使用DNA微阵列的转录组分析显示，fimS的失活导致10%的牙龈卟啉单胞菌基因组的差异表达（>1.5倍; P < 0.05）。值得注意的是，编码七种不同转录调节因子的基因，包括fimR基因和三种胞质外σ因子基因，在fimS突变体中差异表达。
Porphyromonas gingivalis is a late-colonizing bacterium of the subgingival dental plaque biofilm associated with periodontitis. Two P. gingivalis genes, fimR and fimS, are predicted to encode a two-component signal transduction system comprising a response regulator (FimR) and a sensor histidine kinase (FimS). In this study, we show that fimS and fimR, although contiguous on the genome, are not part of an operon. We inactivated fimR and fimS in both the afimbriated strain W50 and the fimbriated strain ATCC 33277 and demonstrated that both mutants formed significantly less biofilm than their respective wild-type strains. Quantitative reverse transcription-real-time PCR showed that expression of fimbriation genes was reduced in both the fimS and fimR mutants of strain ATCC 33277. The mutations had no effect, in either strain, on the P. gingivalis growth rate or on the response to hydrogen peroxide or growth at pH 9, at 41 degrees C, or at low hemin availability. Transcriptome analysis using DNA microarrays revealed that inactivation of fimS resulted in the differential expression of 10% of the P. gingivalis genome (>1.5-fold; P < 0.05). Notably genes encoding seven different transcriptional regulators, including the fimR gene and three extracytoplasmic sigma factor genes, were differentially expressed in the fimS mutant.