毕赤酵母分泌型遗传操作工具的构建与优化

Construction and optimization of secretory genetic manipulation tools in Pichia pastoris

为了解决毕赤酵母遗传操作效率低且流程繁琐的问题,提高其应用价值,构建并优化了分泌型遗传操作工具。首先,以α-淀粉酶为报告蛋白,通过融合自主复制序列构建非整合型表达质粒;其次,借助通用引物和POE-PCR,快速筛选评估与目的蛋白最匹配的内源信号肽;最后,构建以亚磷酸盐为唯一磷源的营养依赖型筛选标记。结果表明:2种非整合型质粒表达α-淀粉酶的酶活分别是整合型质粒的2倍和1.6倍;以FLO10、EXG1和MSB 2为信号肽引导的α-淀粉酶酶活分别是常规信号肽α-MF的2.5倍、1.94倍和1.75倍;亚磷酸脱氢酶基因(ptxD)成功筛选出异源表达α-淀粉酶的重组菌株。研究简化了基因操作流程,改进了遗传操作工具,开发的绿色安全且低成本的营养依赖型筛选标记,有助于毕赤酵母分泌表达系统的应用和推广。

In order to solve the problems of low efficiency and cumbersome process of Pichia pastoris genetic manipulation,secretory genetic manipulation tools were constructed and optimized to improve their industrial production and application value.Firstly,theα-amylase was employed as the reporter protein,and the non-integrated expression plasmid was constructed by fusing the self-replicating sequence.Secondly,endogenous signal peptides that best match the target protein were quickly screened and evaluated using universal primers and POE-PCR.Finally,a nutrition-dependent screening marker was constructed with phosphite as the sole phosphorus source.The results indicate that non-integrated plasmids expressα-amylase with 2-fold and 1.6-fold higher enzyme activity compared to integrated plasmids,respectively;The use of FLO10,EXG1,and MSB2 signal peptides results in 2.5-fold,1.94-fold,and 1.75-fold higherα-amylase activity than the conventional signal peptideα-MF,respectively;Arecombinant strain for heterologous expression ofα-amylase is successfully screened using the phosphite dehydrogenase gene(ptxD).The process of gene operation is simplified,the genetic operation tools are improved,and green,safe,and low-cost nutrition-dependent screening markers are provided,which lays a foundation for the application and promotion of the Pichia pastoris secretory expression system.