Kim Tae Soo, Ahn Ji Yeon, Yoon Jin Ho, Kang Hyen Sam
School of Biological Sciences, Seoul National University, Shillim-Dong, Kwanak-Gu, 151-742 Seoul, Korea.
Curr Genet. 2003 Dec;44(5):261-7. doi: 10.1007/s00294-003-0447-7. Epub 2003 Oct 2.
The expression of STA genes that encode extracellular glucoamylase isozymes is repressed in most laboratory Saccharomyces cerevisiae strains, which are believed to contain an undefined repressor, designated STA10. To identify the regulator involved in STA10 repression, we investigate the FLO8, MSN1, MSS11, STE12, and TEC1 genes. The Deltaflo8 or Deltamss11 deletion mutants in the sta10 genetic background exhibit both a loss of flocculation ability and a reduction in extracellular glucoamylase activity, as in the STA10 strain. Moreover, the STA10 repression is suppressed completely or partially by the introduction of a single copy of the FLO8 or MSS11 genes. Sequence analysis and complementation testing of the STA10 strain reveal that it has an inactive, mutated flo8-1 allele. A random spore analysis and transplacement (allele replacement) experiment confirms that the repressive phenotype of STA10 is due to the amber mutation of the transcriptional activator, FLO8.
在大多数实验室酿酒酵母菌株中，编码胞外葡糖淀粉酶同工酶的STA基因的表达受到抑制，据信这些菌株含有一种未明确的阻遏物，命名为STA10。为了鉴定参与STA10抑制作用的调节因子，我们研究了FLO8、MSN1、MSS11、STE12和TEC1基因。sta10遗传背景下的Deltaflo8或Deltamss11缺失突变体表现出絮凝能力丧失和胞外葡糖淀粉酶活性降低，与STA10菌株情况相同。此外，通过导入单拷贝的FLO8或MSS11基因，STA10的抑制作用被完全或部分抑制。对STA10菌株的序列分析和互补测试表明，它具有一个无活性的、突变的flo8 - 1等位基因。随机孢子分析和转位（等位基因替换）实验证实，STA10的抑制表型是由于转录激活因子FLO8的琥珀突变所致。
