Kaneko Y, Toh-e A, Oshima Y
Mol Cell Biol. 1982 Feb;2(2):127-37. doi: 10.1128/mcb.2.2.127-137.1982.
Two lines of evidence showed that the PHO8 gene encodes the structure of repressible, nonspecific alkaline phosphatase in Saccharomyces cerevisiae: (i) the enzyme produced by a temperature-sensitive pho8 mutant at the permissive temperature (25 degrees C) was more thermolabile than that of the wild-type strain, and (ii) the PHO8 gene showed a gene dosage effect on the enzyme activity. The pho8 locus has been mapped on chromosome IV, 8 centimorgans distal to rna3. A new mutant carrying the pho9 gene was isolated which lacks repressible alkaline phosphatase, but has the normal phenotype for the synthesis of repressible acid phosphatase. The pho9 gene segregated independently of all known pho-regulatory genes and did not show the gene dosage effect on repressible alkaline phosphatase activity. The pho9/pho9 diploid hardly sporulated and showed no commitment to intragenic recombination when it was inoculated on sporulation medium. Hence the pho9 mutant has a phenotype similar to the pep4 mutant, which was isolated as a pleiotropic mutant with reduced levels of proteinases A and B and carboxypeptidase Y. An allelism test indicated that pho9 and pep4 are allelic.
有两条证据表明，PHO8基因编码酿酒酵母中可阻遏的非特异性碱性磷酸酶的结构：（i）温度敏感型pho8突变体在允许温度（25摄氏度）下产生的酶比野生型菌株的酶更不耐热，以及（ii）PHO8基因对酶活性表现出基因剂量效应。pho8基因座已定位在第四条染色体上，距离rna3 8厘摩。分离出了一个携带pho9基因的新突变体，该突变体缺乏可阻遏的碱性磷酸酶，但在可阻遏酸性磷酸酶的合成方面具有正常表型。pho9基因与所有已知的pho调节基因独立分离，并且对可阻遏碱性磷酸酶活性没有表现出基因剂量效应。pho9/pho9二倍体几乎不产孢，当接种在产孢培养基上时，对基因内重组没有表现出倾向。因此，pho9突变体具有与pep4突变体相似的表型，pep4突变体是作为一种多效突变体分离出来的，其蛋白酶A和B以及羧肽酶Y的水平降低。等位性测试表明pho9和pep4是等位基因。
