King H B, Casselton L A
Mol Gen Genet. 1977 Dec 9;157(3):319-25. doi: 10.1007/BF00268669.
Thirteen chromosomal loci have been identified which affect acetate metabolism in Coprinus. Mutants at only two loci, acu-l and acu-7, are deficient in isocitrate lyase (ICL) (EC 4.1.3.1) activity. acu-1 mutants are unable to induce ICL because they lack acetyl-CoA synthetase which is required to convert acetate to the metabolic inducer of ICL. acu-7 is the structural gene for ICL. This was shown by selecting temperature sensitive acu+ revertants resulting from a second mutation within the acu-7 gene. One such revertant was shown to produce an ICL protein which was more thermolabile than the wild type enzyme. Other workers have postulated that ICL activity is important during asexual morphogenesis in fungi. No evidence was found for this in Coprinus. The morphological mutant oidial, which produces abundant asexual spores even in submerged culture, had the same low uninduced level of ICL activity as the wild type. Moreover, an acu-7 mutation had no effect on the expression of the oidial phenotype.
已鉴定出13个影响鬼伞属真菌醋酸盐代谢的染色体位点。只有acu-1和acu-7这两个位点的突变体缺乏异柠檬酸裂解酶（ICL）（EC 4.1.3.1）活性。acu-1突变体无法诱导ICL，因为它们缺乏将醋酸盐转化为ICL代谢诱导物所需的乙酰辅酶A合成酶。acu-7是ICL的结构基因。这是通过选择由acu-7基因内的第二次突变产生的温度敏感acu+回复体来证明的。其中一个这样的回复体被证明产生的ICL蛋白比野生型酶更不耐热。其他研究人员推测，ICL活性在真菌的无性形态发生过程中很重要。但在鬼伞属真菌中未发现相关证据。形态突变体oidial即使在深层培养中也能产生大量无性孢子，其ICL活性的未诱导水平与野生型一样低。此外，acu-7突变对oidial表型的表达没有影响。
