【摘要】 将解除了葡萄糖阻遏的纤维素酶高产菌株瑞氏木霉TrichodermareeseiRutC30经EMS诱变后,在酪蛋白平板上筛选出部分蛋白酶缺陷突变菌株T.reeseiRutC30M3。RutC30M3的胞外蛋白酶活力比亲本株降低约74%,但生长特性、产纤维素酶活力等性状与亲本株相同。用携带潮霉素磷酸转移酶基因(hph)的表达质粒pAN7-1分别转化瑞氏木霉RutC30和RutC30M3原生质体,转化结果显示RutC30M3(pAN7-1)对潮霉素的抗性比RutC30(pAN7-1)提高约20%,而Northernblot分析结果显示在两菌株中潮霉素基因转录水平相似,由此证明宿主菌蛋白酶缺陷对保护重组蛋白免于降解有明显作用。蛋白酶缺陷菌株RutC30M3适于作为瑞氏木霉外源基因表达系统中的受体菌株用于大量生产同源与异源蛋白。更多还原

【Abstract】 Cellulase overproducing and glucose repressor CreI-deficient Trichoderma reesei RutC30 was mutagenized by using EMS, and an extracellular protease-deficient strain RutC30M3 has been isolated on casein plate and characterized. The extracellular protease activities of T. reesei RutC30M3 were 26% of the parent strain, but the growth properties and cellulase activities was identical to RutC30. The comparison of expression-secretion level of heterologous gene in T. reesei RutC30M3 and RutC30 was carried out with hygromycin resistance gene hph as reporter. The result indicated that the level of expression-secretion of HPH in RuC30M3 has increased by 20% over the RutC30, but the transcriptional level of hph gene in both strains were similar by Northern blot analysis. Therefore, the protease-deficient strain T. reesei RutC30M3 was suitable to be the recipient strain in the heterologous gene expression system of T. reesei.更多还原