Transcriptional analysis of mutacin I (mutA) gene expression in planktonic and biofilm cells of Streptococcus mutans using fluorescent protein and glucuronidase reporters
Transcriptional analysis of mutacin I (mutA) gene expression in planktonic and biofilm cells of Streptococcus mutans using fluorescent protein and glucuronidase reporters
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DOI：
10.1111/j.1399-302x.2004.00148.x
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发表时间：
2004-08-01
影响因子：
--
通讯作者：
Qi, F
中科院分区：
文献类型：
--
作者：
Kreth, J;Merritt, J;Qi, F
变形链球菌是参与龋齿发展的主要病原体。S.变形杆菌是促进细菌在牙菌斑中占优势的主要毒力因子之一。虽然已经揭示了很多关于突变蛋白的生化结构，但对突变蛋白基因的表达和调控知之甚少，这主要是由于缺乏适当的方法来监测突变蛋白基因的表达，特别是在生物膜条件下。在这项研究中，一套报告系统的绿色荧光蛋白（gfp），单体红色荧光蛋白（mrfp 1），和葡萄糖醛酸酶（gusA）被引入到S。研究mutacin I基因（穆塔）的转录活性。虽然mutA-报告基因融合体在染色体上是单拷贝的，但这些报告基因系统显示出强信号，使我们能够有效地监测S.变异体使用这些报告系统，我们表明，穆塔的表达，在两个促分化和生物膜细胞，即使突变蛋白的活动通常只在生物膜细胞中检测。此外，我们确认mutR，基因上游的变构素操纵子，是所需的变构素I基因表达。本研究的成功验证了利用这些报告系统研究S.变异体
Streptococcus mutans is implicated as the primary pathogen involved in the development of dental caries. The production of specific bacteriocins (called mutacins) by S. mutans is one of the major virulence factors which facilitate the dominance of the bacterium within dental plaque. While much has been revealed about the biochemical structures of mutacins, little is known about the expression and regulation of mutacin genes, largely due to the lack of proper methods to monitor mutacin gene expression, especially under biofilm conditions. In this study, a set of reporter systems with the green fluorescent protein (gfp), the monomeric red fluorescent protein (mrfp1), and the glucuronidase (gusA) are introduced to S. mutans to study the transcriptional activities of the mutacin I gene (mutA). Although the mutA-reporter fusions are in single copy on the chromosome, these reporter systems display strong signals that allow us to effectively monitor mutA gene expression in S. mutans. Using these reporter systems, we show that mutA is expressed in both planktonic and biofilm cells, even though mutacin activities are normally detected only in biofilm cells. Furthermore, we confirm that mutR, the gene upstream of the mutacin operon, is required for mutacin I gene expression. The success of this study validates the feasibility of using these reporter systems to study gene expression and regulation in S. mutans.