Transcriptional analysis of gtfB, gtfC, and gbpB and their putative response regulators in several isolates of Streptococcus mutans.
Transcriptional analysis of gtfB, gtfC, and gbpB and their putative response regulators in several isolates of Streptococcus mutans.
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DOI：
10.1111/j.1399-302x.2008.00451.x
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发表时间：
2008-12
影响因子：
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通讯作者：
R. N. Stipp;R. Gonçalves;J. F. Höfling;Daniel J. Smith;R. MATTOS-GRANER
中科院分区：
文献类型：
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作者：
R. N. Stipp;R. Gonçalves;J. F. Höfling;Daniel J. Smith;R. MATTOS-GRANER
背景技术变形链球菌是一种主要的龋齿病原体，表达多种毒力基因，这些毒力基因介导其生长、在牙齿表面上的积累以及酸介导的牙齿脱矿质。 GTFB 和 GtfC 催化蔗糖在细胞外合成不溶于水的葡聚糖基质，对于牙齿生物膜中细菌的积累至关重要。 GbpB 是变形链球菌的一种必需蛋白，也可能介导细胞表面与葡聚糖的相互作用。目的/方法在本研究中，我们测定了 11 种变形链球菌菌株中 gtfB、gtfC 和 gbpB 的转录水平，以及几种假定的转录反应调节因子 (rr) 在浮游生长不同阶段的情况。结果 gtfB 和 gtfC 的活性依赖于生长阶段，并且在特定的生长阶段在几个菌株中呈现出不同的模式，而 gbpB 活性似乎受到生长阶段的适度影响。 rr vicR、covR、comE、ciaR 和 rr1 的转录模式具有生长阶段依赖性，其中一些基因以高度协调的方式表达。除 comE 外，所有菌株均表达每个 rr。然而，毒力和调节基因的模式是菌株特异性的。结论 这些发现表明，控制毒力基因表达的机制在基因型之间存在差异，这提供了变形链球菌的遗传多样性可能对理解该物种毒力基因表达的调节机制具有重要意义的观点。
BACKGROUND Streptococcus mutans, a major dental caries pathogen, expresses several virulence genes that mediate its growth, accumulation on tooth surfaces, and acid-mediated tooth demineralization. GtfB and GtfC catalyze the extracellular synthesis of water-insoluble glucan matrix from sucrose, and are essential for accumulation of bacteria in the dental biofilm. GbpB, an essential protein of S. mutans, might also mediate cell-surface interaction with glucan. AIM/METHODS In this study, we determined the transcription levels of gtfB, gtfC, and gbpB, and several putative transcriptional response regulators (rr) at different phases of planktonic growth in 11 S. mutans strains. RESULTS Activities of gtfB and gtfC were growth-phase dependent and assumed divergent patterns in several strains during specific phases of growth, while gbpB activities appeared to be under modest influence of the growth phase. Transcription patterns of the rr vicR, covR, comE, ciaR, and rr1 were growth-phase dependent and some of these genes were expressed in a highly coordinated way. Each rr, except comE, was expressed by all the strains. Patterns of virulence and regulatory genes were, however, strain-specific. CONCLUSIONS The findings suggest that mechanisms controlling virulence gene expression are variable among genotypes, providing the notion that the genetic diversity of S. mutans may have important implications for understanding mechanisms that regulate the expression of virulence genes in this species.