【摘要】 目的研究转录调控蛋白PrfA对两组新近发现的单核细胞增生李斯特菌基因的体外转录作用。方法利用本室近年来建立的体外转录系统,对两组基于转录基因组体内研究发现的5个可能的受PrfA不同调节的单核细胞增生李斯特菌基因进行了体外转录活性的研究。结果第一组中的hpt基因的体外转录活性受PrfA正调节,而其它4个基因既不被PrfA正调节也不被负调节。结论除hpt基因外,其它4个基因体外转录结果与体内实验不相一致,说明PrfA在体内可能通过复杂多样的非直接方式、或者还需要一些目前未知的因子来调控这些新近发现的基因的表达。更多还原

【Abstract】 Objective The aim of study was to investigate PrfA-dependent transcription activities of two groups of newly identified and putatively in vivo PrfA-regulated genes of listeria monocytogenes. Methods Transcription initiation at promoters of five genes selected from the two groups based on the transcriptome analysis was studied by means of in vitro transcription system. Results The data showed that, among these new putative "PrfA-regulated" promoters, only the promoter of hpt gene belonging to group I was significantly activated by PrfA. In addition, this promoter was the only one exhibiting all essential features of a typical PrfA-dependent promoter. Neither positively nor negatively, was in vitro transcription starting at most of other promoters affected by PrfA.Conclusion These in vitro transcription results indicate that the effect of PrfA in vivo on the expression of these new genes might be committed in an indirect manner or via a complex process, and that the PrfA-mediated transcription of these genes, in contrast to the PrfA-dependent transcription of the known virulence genes (including hpt), probably requires additional factors lacked in the in vitro transcription system.更多还原