Transcriptional control of glucoamylase synthesis in vegetatively growing and sporulating Saccharomyces species.
Transcriptional control of glucoamylase synthesis in vegetatively growing and sporulating Saccharomyces species.
复制标题
营养生长和产孢酵母菌中葡糖淀粉酶合成的转录控制。
DOI：
10.1128/mcb.6.9.3034-3041.1986
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发表时间：
1986
影响因子：
5.3
通讯作者：
Marmur,J
中科院分区：
文献类型：
--
作者：
Pretorius,IS;Modena,D;Vanoni,M;Englard,S;Marmur,J
在saccharomycesspecies中，三个未连锁的同源基因STA1、STA2和sta3分别编码胞外糖基化葡萄糖淀粉酶同工酶I、II和III。在单倍体中缺乏功能性stagene的cerevisiae，确实携带仅在孢子形成过程中表达的葡萄糖淀粉酶基因∆sta (W. J. Colonna and P. T. Magee， J.细菌学杂志，34:844-853,1978；I. Yamashita和S. Fukui, Mol. Cell。《圣经》5:3069-3073,1985)。在这项研究中，我们研究了一些影响葡萄糖淀粉酶表达的生理和遗传因素。研究发现，在合成培养基中生长的sta2菌株仅在麦芽糖蛋白M365（一种低麦芽糖混合物）或淀粉存在的情况下产生葡萄糖淀粉酶。葡萄糖淀粉酶活性最高的细胞生长在富含甘油和乙醇、淀粉或麦芽糖精的培养基中。当各种糖作为碳源时，它们都支持葡萄糖淀粉酶的合成，尽管水平较低。在任何给定的生长培养基中，葡萄糖淀粉酶同工酶II的合成受线粒体功能的调节。葡萄糖淀粉酶的合成在整个生长阶段都是连续的，最大的分泌发生在稳定期的早期。在不同的方案中，酶积累的差异是由葡萄糖淀粉酶mRNA水平的差异引起的。在mata /MATα二倍体和调控基因esta10的存在下，葡萄糖淀粉酶mRNA和酶活性均受到显著和协调的抑制。当sta2基因存在于多拷贝质粒中时，这两种效应都被部分克服。在STA2/STA2二倍体中，STA2 mRNA与葡萄糖淀粉酶共诱导。aSTA2探针的Northern blotting也检测到一个较小的共诱导RNA种。在产孢体二倍体中检测到相同的mRNA物种，并且可能编码产孢特异性葡萄糖淀粉酶。
Three unlinked, homologous genes,STA1,STA2, andSTA3, encode the extracellular glycosylated glucoamylase isozymes I, II, and III, respectively, inSaccharomycesspecies.S. cerevisiae, which issta0(absence of functionalSTAgenes in haploids), does carry a glucoamylase gene, ∆sta, expressed only during sporulation (W. J. Colonna and P. T. Magee, J. Bacteriol. 134:844-853, 1978; I. Yamashita and S. Fukui, Mol. Cell. Biol. 5:3069-3073, 1985). In this study we examined some of the physiological and genetic factors that affect glucoamylase expression. It was found thatSTA2 strains grown in synthetic medium produce glucoamylase only in the presence of either Maltrin M365 (a mixture of maltooligosaccharides) or starch. Maximal levels of glucoamylase activity were found in cells grown in rich medium supplemented with glycerol plus ethanol, starch, or Maltrin. When various sugars served as carbon sources they all supported glucoamylase synthesis, although at reduced levels. In any given growth medium glucoamylase isozyme II synthesis was modulated by functionality of the mitochondria. Synthesis of glucoamylase is continuous throughout the growth phases, with maximal secretion taking place in the early stationary phase. In the various regimens, the differences in enzyme accumulation are accounted for by differences in the levels of glucoamylase mRNA. Both glucoamylase mRNA and enzyme activity were drastically and coordinately inhibited inMATa/MATα diploids and by the presence of the regulatory geneSTA10. Both effects were partially overcome when theSTA2 gene was present on a multicopy plasmid. TheSTA2 mRNA and glucoamylase were coinduced in sporulatingSTA2/STA2 diploids. A smaller, coinduced RNA species was also detected by Northern blotting with aSTA2 probe. The same mRNA species was detected in sporulatingsta0diploids and is likely to encode the sporulation-specific glucoamylase.