Functional Genomics of Enterococcus faecalis: Multiple Novel Genetic Determinants for Biofilm Formation in the Core Genome
Functional Genomics of Enterococcus faecalis: Multiple Novel Genetic Determinants for Biofilm Formation in the Core Genome
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DOI：
10.1128/jb.01688-08
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发表时间：
2009-04-15
影响因子：
3.2
通讯作者：
Dunny, Gary M.
中科院分区：
文献类型：
--
作者：
Ballering, Katie S.;Kristich, Christopher J.;Dunny, Gary M.
粪肠球菌在宿主组织和非生物表面（如导管）上形成坚固的生物膜的能力可能在机会性耐药粪肠球菌感染的发病机制和抗生素耐药基因的转移中发挥重要作用。我们对粪肠杆菌核心基因组中生物膜形成的遗传决定因素进行了全面分析。在这里，我们描述了68个基因位点预测参与生物膜的形成，通过重组酶体内表达技术（RIVET）鉴定；这些基因中的大多数以前没有被研究过。定量逆转录- pcr证实了这些决定因素在生物膜生长过程中的差异表达，遗传互补研究证实了几个候选基因在生物膜形成中的作用。特别感兴趣的是基因座EF1809，预计编码GntR家族的调节蛋白。我们在RIVET筛选中分离了14个独立的非兄弟克隆，其中包含该基因的假定启动子区域；在生物膜生长过程中，EF1809基因的表达量增幅最大。由于EF1809的框架内缺失导致严重的生物膜缺陷，可以通过克隆的野生型基因补充，我们将EF1809命名为ebrA（肠球菌生物膜调节剂）。在我们的研究中发现的大多数新基因位点在革兰氏阳性细菌病原体中高度保守，因此可能构成一个参与生物膜形成的未表征基因库，可能是药物发现的有用靶点。
The ability of Enterococcus faecalis to form robust biofilms on host tissues and on abiotic surfaces such as catheters likely plays a major role in the pathogenesis of opportunistic antibiotic-resistant E. faecalis infections and in the transfer of antibiotic resistance genes. We have carried out a comprehensive analysis of genetic determinants of biofilm formation in the core genome of E. faecalis. Here we describe 68 genetic loci predicted to be involved in biofilm formation that were identified by recombinase in vivo expression technology (RIVET); most of these genes have not been studied previously. Differential expression of a number of these determinants during biofilm growth was confirmed by quantitative reverse transcription-PCR, and genetic complementation studies verified a role in biofilm formation for several candidate genes. Of particular interest was genetic locus EF1809, predicted to encode a regulatory protein of the GntR family. We isolated 14 independent nonsibling clones containing the putative promoter region for this gene in the RIVET screen; EF1809 also showed the largest increase in expression during biofilm growth of any of the genes tested. Since an in-frame deletion of EF1809 resulted in a severe biofilm defect that could be complemented by the cloned wild-type gene, we have designated EF1809 ebrA (enterococcal biofilm regulator). Most of the novel genetic loci identified in our studies are highly conserved in gram-positive bacterial pathogens and may thus constitute a pool of uncharacterized genes involved in biofilm formation that may be useful targets for drug discovery.