黑曲霉糖化酶基因表达调控的研究 Ⅰ.高产及低产菌株糖化酶表达的总体分析和比较  

STUDIES ON THE REGULATION OF GLUCOAMYLASE GENE (glaA) EXPRESSION IN A. NIGER I. THE OVERALL ANALYSIS AND COMPARISON OF THE EXPRESSION OF GLUCOAMYLASE IN THE OVERPRODUCING STRAIN A. NIGER T21 AND ITS ORIGINAL STRAIN A. NIGER 3.795

作　　者：乔殿华[1] 唐国敏[1] 钟丽婵[1] 郗乔然[1] 杨开宇[1] 

机构地区：[1]中国科学院微生物研究所,北京100080

出　　处：《微生物学报》1997年第5期349-354,共6页Acta Microbiologica Sinica

基　　金：国家自然科学基金;联合国教科文组织资助项目

摘　　要：对黑曲霉(Aspergillus niger)高产菌株T21和原始菌株3.795糖化酶的基因表达从菌体生长、酶形成动力学、glaA基因拷贝数、糖化酶mRNA含量及其稳定性等多个方面进行了分析和比较。T21和3.795糖化酶的大量产生均自菌体生长的静止期开始。培养72h后,两者的菌体浓度相同,但T2l产生的糖化酶量为3.795的10～17倍,说明糖化酶产量的差异不是因生物量或酶起始合成期不同引起的,而是由于细胞内酶表达量不同引起的。Northern杂交显示T21总RNA中糖化酶mRNA含量为3.795的4.3～4.4倍.两菌株glaA基因拷贝数及糖化酶mRNA的稳定性分析结果排除了这两个因素的影响,因此T21糖化酶mRNA含量的增加主要是glaA基因转录水平提高的结果。T21与3.795之间糖化酶水平差异(10～17倍)与糖化酶mRNA水平差异(4.3～4.4倍)的不一致性,提示T21和3.795之间除转录水平外可能还存在着翻译水平上的差异(2～4倍)。此外,T21和3.795均存在着对糖化酶基因表达的碳源调控机制,根据两者在淀粉、麦芽糖和葡萄糖培养条件下所产生的mRNA比均为4:3:2,可以认为,这种调控作用发生在转录水平上,并且具有相同的调控方式。Expression of the A. niger T21 and 3.795 glaA gene was investigated with respect to the growth of mycelia, producing of glucoamylase, copy number of glaA gene as well as glucoamylase mRNA level and its stability. Both A. niger T21 and 3.795 produced substantial glucoamylase at the stable phase when their biomass were the same. After incubating for 72 hours, while the biomass remained the same, the glucoamylase produced by T21 was 10- 17 times higher than that by 3.795. Northern analysis showed that in the total RNA from T21 4.3 - 4.4 fold as much glucoamylase mRNA as from 3.795 was determined. This result along with results with regard to copy number of glaA gene and stability of glucoamylase mRNA supported the suggestion that the increased mRNA level of glucoamylase was contributed by the increasing at transcription level. The inconsistancy between the difference of enzyme production (10-17 fold) and that of the mRNA level (4.3 - 4.4 fold) revealed that some difference at translation exist probably. Furthermore, expression of both T21 and 3.795 glaA gene was regulated by carbon sources, this regulation occured at transcription level in the same manner and also probably occured at translation level.

关 键 词：真菌 黑曲霉 糖化酶 表达调控 基因表达 

分 类 号：Q949.327.1[生物学—植物学]