Effect of an orphan response regulator on Streptococcus mutans sucrose-dependent adherence and cariogenesis
Effect of an orphan response regulator on Streptococcus mutans sucrose-dependent adherence and cariogenesis
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DOI：
10.1128/iai.71.8.4351-4360.2003
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发表时间：
2003-08-01
影响因子：
3.1
通讯作者：
Spatafora, G
中科院分区：
文献类型：
--
作者：
Idone, V;Brendtro, S;Spatafora, G
变形链球菌是牙菌斑的主要致酸成分，牙菌斑使牙釉质脱矿，导致蛀牙。细胞相关的葡萄糖基转移酶催化蔗糖依赖的粘性葡聚糖聚合物的合成，与葡聚糖结合蛋白一起，促进变形链球菌粘附在牙齿上和细胞聚集。我们在无菌大鼠中产生了一个S. mutans Tn916转座子突变体GMS315，该突变体在蔗糖依赖性粘附方面存在缺陷，并且与UA130野生型祖细胞相比，其龋齿性显著降低。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、Western blotting和n端序列分析结果证实，GMS315蛋白谱中不存在155 kda的葡萄糖基转移酶S （Gtf-S）。对GMS315中独特转座子插入的定位揭示了位于gcrR上游的一个假定调控区域的破坏，该基因先前由Sato等人描述，与其他细菌反应调节因子具有重要的氨基酸一致性（Y. Sato， Y. Yamamoto, and H. Kizaki, FEMS Microbiol）。《社会科学》第186期：187-191页，2000)。gcrR调节因子，我们称之为“tarC”，并不与13种提出的双组分信号转导系统中的任何一种一致，这些信号转导系统来源于对变形链球菌基因组的计算机分析，而是代表基因组中几种孤儿反应调节因子之一。Northern杂交和/或实时逆转录- pcr实验的结果显示，在tarC敲除突变体（GMS900）中，Gtf-S和葡聚糖结合蛋白C （GbpC）的表达增加，从而支持了tarC作为负转录调节因子的观点。此外，我们注意到，相对于野生型，GMS900改变了生物膜结构，并且在无菌大鼠中降低了龋齿性。综上所述，这些发现支持了信号转导在变形葡萄球菌蔗糖依赖性粘附和聚集中的作用，并暗示TarC是控制变形葡萄球菌诱导的龋齿发生的潜在靶点。
Streptococcus mutans is the principal acidogenic component of dental plaque that demineralizes tooth enamel, leading to dental decay. Cell-associated glucosyltransferases catalyze the sucrose-dependent synthesis of sticky glucan polymers that, together with glucan binding proteins, promote S. mutans adherence to teeth and cell aggregation. We generated an S. mutans Tn916 transposon mutant, GMS315, which is defective in sucrose-dependent adherence and significantly less cariogenic than the UA130 wild-type progenitor in germfree rats. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and N-terminal sequence analysis confirmed the absence of a 155-kDa glucosyltransferase S (Gtf-S) from GMS315 protein profiles. Mapping of the unique transposon insertion in GMS315 revealed disruption of a putative regulatory region located upstream of gcrR, a gene previously described by Sato et al. that shares significant amino acid identity with other bacterial response regulators (Y. Sato, Y. Yamamoto, and H. Kizaki, FEMS Microbiol. Lett. 186: 187-191, 2000). The gcrR regulator, which we call "tarC," does not align with any of the 13 proposed two-component signal transduction systems derived from in silico analysis of the S. mutans genome, but rather represents one of several orphan response regulators in the genome. The results of Northern hybridization and/or real-time reverse transcription-PCR experiments reveal increased expression of both Gtf-S and glucan binding protein C (GbpC) in a tarC knockout mutant (GMS900), thereby supporting the notion that TarC acts as a negative transcriptional regulator. In addition, we noted that GMS900 has altered biofilm architecture relative to the wild type and is hypocariogenic in germfree rats. Taken collectively, these findings support a role for signal transduction in S. mutans sucrose-dependent adherence and aggregation and implicate TarC as a potential target for controlling S. mutans-induced cariogenesis.