REGULATION OF GROUP B STREPTOCOCCI CAPSULE EXPRESSION

B 族链球菌荚膜表达的调节

• 批准号: 6362262
• 负责人: Daniel W Shelver
• 金额: $ 4.02万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6362262
• 关键词: Streptococcus agalactiae; bacteria infection mechanism; bacterial capsules; bacterial polysaccharides; enzyme linked immunosorbent assay; gene expression; genetic promoter element; genetic regulation; genetic regulatory element; genetic transcription; microorganism genetics; molecular cloning; molecular pathology; phenotype; polymerase chain reaction; regulatory gene; virulence

DESCRIPTION This proposal seeks to define elements that control the transcriptional regulation of an important virulence factor of a prevalent neonatal human pathogen, Streptococcus agalactiae. The capsular polysaccharide (CPS) or GBS is an important virulence factor and its regulation may contribute to the virulence of this organism. GBS demonstrate growth phase regulation of CPS biosynthesis; however, it is not known what mechanisms control this regulation. The sequence of the CPS biosynthetic operon (cpsIII) suggests that trans-acting factors and cis-acting elements regulate expression of CPS. In this proposal, a genetic approach will be taken to determine if two putative regulatory proteins play a role in the transcriptional regulation of CPS biosynthesis. The cpsY gene (an ORF divergently transcribed from the cpsIII operon), which shows similarity to LysR-type DNA-binding transcriptional regulators, will be inactivated by the insertion of a kanamyin resistance cassette. The cpsX gene is the first gene in the cpsIII operon and encodes a putative transmembrane regulator. The cpsX gene will be inactivated with an in frame deletion. The resulting mutants will be evaluated for transcriptional activity and growth phase regulation of cpsIII transcription. Additionally, regions of symmetry that may reflect cis-acting regulatory elements will be examined for their effects on transcriptional activity of the cpsIII operon.

描述 本提案旨在定义控制流行的新生儿人类病原体无乳链球菌的重要毒力因子转录调节的元件。荚膜多糖（CPS）或GBS是一种重要的毒力因子，其调节可能有助于该生物体的毒力。 GBS 证明了 CPS 生物合成的生长阶段调节；然而，尚不清楚是什么机制控制这种调节。 CPS 生物合成操纵子 (cpsIII) 的序列表明反式作用因子和顺式作用元件调节 CPS 的表达。在该提案中，将采用遗传方法来确定两种假定的调节蛋白是否在 CPS 生物合成的转录调节中发挥作用。 cpsY 基因（从 cpsIII 操纵子转录而来的 ORF）与 LysR 型 DNA 结合转录调节因子相似，将通过插入卡那霉素抗性盒而失活。 cpsX 基因是 cpsIII 操纵子中的第一个基因，编码假定的跨膜调节因子。 cpsX 基因将因框内删除而失活。将评估所得突变体的转录活性和cpsIII转录的生长期调节。此外，将检查可能反映顺式作用调节元件的对称区域对 cpsIII 操纵子转录活性的影响。