Nikawa J, Sugiyama M, Hayashi K, Nakashima A
Department of Biochemical Engineering and Science, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan.
Gene. 1997 Nov 12;201(1-2):5-10. doi: 10.1016/s0378-1119(97)00418-6.
We previously reported that the Saccharomyces cerevisiae ire15 mutation results in an inositol-auxotrophic phenotype, and that human cDNAs can suppress the ire15 mutation (Nikawa, J., 1994. A cDNA encoding the human transforming growth factor beta receptor suppresses the growth defect of a yeast mutant. Gene 149, 367 372; Nikawa, J., Nakano, H., Ohi, N., 1996b. Structural and functional conservation of human and yeast HAC1 genes which can suppress the growth defect of the Saccharomyces cerevisiae ire15 mutant. Gene 171, 107-111). Herein, we present evidence that the gene responsible for the ire15 mutation is HAC1, which encodes a transcription factor for KAR2, obtained by isolating a yeast single-copy supressor gene and by performing complementation analysis. Sequencing analysis revealed that the mutant HAC1 gene obtained from the ire15 mutant contained an AAA codon at position 50 instead of the AGA codon observed in the wild-type gene, resulting in the alteration of the aa from Arg to Lys. All human cDNAs and yeast multicopy suppressors, which had been isolated as suppressors for the ire15 mutation, were able to suppress the inositol-auxotrophic phenotype but not the defect in KAR2 induction of the hac1-disrupted strain.
我们之前报道过，酿酒酵母ire15突变会导致肌醇营养缺陷型表型，并且人类cDNA可以抑制ire15突变（二阶川，J.，1994年。编码人类转化生长因子β受体的cDNA可抑制酵母突变体的生长缺陷。《基因》149卷，367 - 372页；二阶川，J.，中野，H.，大日，N.，1996年b。人类和酵母HAC1基因的结构与功能保守性，其可抑制酿酒酵母ire15突变体的生长缺陷。《基因》171卷，107 - 111页）。在此，我们提供证据表明，负责ire15突变的基因是HAC1，它编码KAR2的转录因子，这是通过分离酵母单拷贝抑制基因并进行互补分析得到的。测序分析显示，从ire15突变体获得的突变型HAC1基因在第50位含有AAA密码子，而非野生型基因中观察到的AGA密码子，导致氨基酸从精氨酸变为赖氨酸。所有作为ire15突变抑制子分离得到的人类cDNA和酵母多拷贝抑制子，都能够抑制肌醇营养缺陷型表型，但不能抑制hac1缺失菌株中KAR2诱导的缺陷。
