Saccharomyces酵母におけるホスファターゼ生産の遺伝制御

概要

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The mechanism by which gene expression is regulated is a fundamental problem not only in genetics but also in the field of applied microbiology. We have made an attempt to genetically uncover the mechanism underlying it with the use of the acid phosphatase system of the yeast Saccharomyces cerevisiae as a model. Many mutants concerning derepression of acid phosphatase have been isolated and characterized, and we discovered the presence of one structural gene (PHO5) and five regulatory genes (PHO2,PHO4,PHO80,PHO81,and PHO85). Among these regulatory genes, we found that two of them, PHO2 and PHO4,play a positive role and another two, PHO80 and PHO85,play a negative role which apparently resembles that of a repressor in the prokaryotic system. A constitutive mutation, designated as PHO83,which most probably occurred in the 5'-non-coding region of the PHO5 gene, was also described. From genetic analyses of these regulatory genes, we proposed a genetic model for the regulation of the synthesis of repressible acid phosphatase; (i) activated positive factors which interact with the promoter of the PHO5 gene are indispensable for the derepression of acid phosphatase, (ii) negative factors express their effect by interfering with the function of the positive factors at a cytoplasmic level, and (iii) inorganic phosphate activates negative factors with the aid of the PHO81 product.
社団法人日本生物工学会の論文
1983-01-25