中文摘要：

【目的】分析杀念菌素/FR-008生物合成途径中转运基因fscTⅠ和fscTⅡ的功能。【方法】构建转运基因fscTⅠ和fscTⅡ的敲除质粒pJTU4137,并通过接合转移和同源重组双交换的方法得到转运基因缺失突变株。转运基因fscTⅠ和fscTII也被克隆到高拷贝质粒pJTU1278上用于在链霉菌FR-008（Streptomyces sp.FR-008）的衍生菌株ZYJ-6中进行转运蛋白的过量表达。【结果】获得了转运蛋白缺失的双交换突变株LX10,发酵结果显示该突变株不再产生杀念菌素及其衍生物;过量表达转运蛋白的基因工程菌株LX11,其杀念菌素的产量约是对照菌株的1.5倍。【结论】体内遗传实验进一步证实FR-008生物合成途径中的fscTⅠ和fscTⅡ是ATP依赖的ABC转运基因,fscTⅠ与fscTⅡ的过量表达增加了杀念菌素的产量,为利用此方法提高其它多烯类抗生素的产量提供了例证。

英文摘要：

[Objective]To investigate function of transporter genes fscTⅠ and fscTⅡ in the biosynthetic gene cluster of candicidin/FR-008.[Methods]We constructed a plasmid pJTU4137 for disruption of transporter genes fscTⅠ and fscTⅡ by conjugation and homologous recombinant.The transporter genes were also PCR amplified and cloned into the high-copy plasmid pJTU1278 for overexpression in strain ZYJ-6 derived from Streptomyces sp.FR-008.[Results]The disruption mutant LX10 was unable to produce candicidin and its analogues.Overexpression of FscTI and FscTⅡ in ZYJ-6 caused a 1.5-fold increase in FR-008-Ⅲ production compared with the control.[Conclusion]We confirmed that fscTⅠ and fscTⅡ are function as ATP dependent ATP binding cassetle（ABC） transporters in the biosynthetic gene cluster of FR-008.Furthermore,a positive example was provided for improving antibiotic production in other polyene producing strains based on the results that overexpression of fscTⅠ and fscTⅠ increased candicidin production.