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首页> 外文期刊>Journal of bacteriology >Gene Expression Analysis of the Streptococcus pneumoniae Competence Regulons by Use of DNA Microarrays
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Gene Expression Analysis of the Streptococcus pneumoniae Competence Regulons by Use of DNA Microarrays

机译：肺炎链球菌能力调节基因的DNA表达分析。

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Competence for genetic transformation in Streptococcus pneumoniae is coordinated by the competence-stimulating peptide (CSP), which induces a sudden and transient appearance of competence during exponential growth in vitro. Models of this quorum-sensing mechanism have proposed sequential expression of several regulatory genes followed by induction of target genes encoding DNA-processing-pathway proteins. Although many genes required for transformation are known to be expressed only in response to CSP, the relative timing of their expression has not been established. Overlapping expression patterns for the genes cinA andcomD (G. Alloing, B. Martin, C. Granadel, and J. P. Claverys, Mol. Microbiol. 29:75–83, 1998) suggest that at least two distinct regulatory mechanisms may underlie the competence cycle. DNA microarrays were used to estimate mRNA levels for all known competence operons during induction of competence by CSP. The known competence regulatory operons, comAB, comCDE, andcomX, exhibited a low or zero initial (uninduced) signal, strongly increased expression during the period between 5 and 12 min after CSP addition, and a decrease nearly to original values by 15 min after initiation of exposure to CSP. The remaining competence genes displayed a similar expression pattern, but with an additional delay of approximately 5 min. In a mutant defective in ComX, which may act as an alternate sigma factor to allow expression of the target competence genes, the same regulatory genes were induced, but the other competence genes were not. Finally, examination of the expression of 60 candidate sites not previously associated with competence identified eight additional loci that could be induced by CSP.
机译：肺炎链球菌的遗传转化能力由能力刺激肽（CSP）协调，该肽在体外以指数方式生长时诱导能力的突然和短暂出现。这种群体感应机制的模型提出了几个调节基因的顺序表达，然后诱导编码DNA加工途径蛋白的靶基因。尽管已知转化所需的许多基因仅在响应CSP时才表达，但尚未确定其表达的相对时间。 cinA 和 comD 基因的重叠表达模式（G. Alloing，B。Martin，C。Granadel和JP Claverys，Mol。Microbiol。29：75-83， （1998年）表明能力周期可能至少存在两种​​不同的监管机制。 DNA微阵列用于评估CSP诱导能力过程中所有已知能力操纵子的mRNA水平。已知的能力调控操纵子 comAB ， comCDE 和 comX 表现出低或零的初始（未诱导）信号，在此过程中表达大大增强加入CSP后5到12分钟的时间，到开始接触CSP后15分钟降低到原始值。其余的能力基因表现出相似的表达模式，但有大约5分钟的额外延迟。在ComX的一个缺陷突变​​体中，它可能是一个替代的sigma因子，可以表达目标能力基因，但诱导了相同的调节基因，而其他能力基因却没有。最后，检查以前与能力无关的60个候选位点的表达，确定了CSP可以诱导的8个其他位点。

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