slnN基因在盐霉素生物合成中的调控功能分析

Regulation of slnN gene in salinomycin biosynthesis

摘要:

[目的]研究盐霉素生物合成基因簇上游潜在调控基因slnN的功能。[方法]本实验利用遗传操作技术，分别对白色链霉菌出发菌株Streptomyces albus BK3-25中的slnN基因进行敲除和过表达，然后利用抑菌圈实验和发酵实验，分别检测不同衍生菌株中盐霉素生物合成产量的变化。同时利用qRT-PCR分析衍生菌株与原始出发菌株之间的结构基因表达差异。[结果]结果表明在slnN基因缺失株（slnNDM）中，盐霉素的表达水平提高了35%左右；而在slnN基因过表达株（slnNOE）中，盐霉素产量下降达43%左右。qRT-PCR分析进一步发现slnN基因缺失，会引起slnO和slnA1基因的上调；而slnN基因过表达后，一方面会下调slnO与slnA1基因的表达，另一方面引起slnT1、slnF基因上调。[结论]本研究证实slnN基因对盐霉素的生物合成具有明显的负调控作用，其机制有待进一步研究。

Abstract:

[Objective] To study the potential of regulatory gene slnN upstream of salinomycin biosynthesis gene cluster. [Methods] We used genetic manipulation technique to knock out and overexpress the slnN gene in the original strain Streptomyces albus BK3-25. Then, using inhibition zone test and fermentation experiment, we detected the changes of the production of salinomycin biosynthesis in different derivative strains. At the same time, we used qRT-PCR technique to analyze the difference of the structural gene expression between the derived strains and the original strain. [Results] The production of salinomycin was increased by about 35% in the slnN gene-deleted strain (slnNDM), whereas the production of salinomycin was decreased by about 43% in the slnN gene-overexpressing strain (slnNOE). qRT-PCR analysis revealed that loss of slnN gene caused up-regulation of slnO and slnA1 genes. The slnN gene overexpression, on the one hand down-regulated the expression of slnO and slnA1 gene, on the other hand caused slnT1 and slnF gene up-regulation. [Conclusion] The slnN gene has a significant negative regulatory effect on the biosynthesis of salinomycin.