Romero D, Dávila G
J Bacteriol. 1986 Sep;167(3):1043-7. doi: 10.1128/jb.167.3.1043-1047.1986.
Neurospora crassa cells require glutamate synthase activity for growth under ammonium-limiting conditions. Despite the physiological importance of glutamate synthase, little is known about the genetics of its expression. To identify the glutamate synthase structural gene, we isolated three new mutants lacking this activity. All mutations are recessive to the wild-type allele and belong to the same complementation group as the previously described en(am)-2 (C24) mutation. Two lines of evidence indicate that en(am)-2 is the structural gene for glutamate synthase in N. crassa. The en(am)-2+ gene shows a gene dosage effect on enzyme activity, and some mutants lacking glutamate synthase activity have cross-reacting material. These data suggest that the mutations are located in the structural gene for N. crassa glutamate synthase.
粗糙脉孢菌细胞在铵限制条件下生长需要谷氨酸合酶活性。尽管谷氨酸合酶具有重要的生理意义，但其表达的遗传学情况却知之甚少。为了鉴定谷氨酸合酶结构基因，我们分离出了三个缺乏该活性的新突变体。所有突变对野生型等位基因均为隐性，并且与先前描述的en(am)-2 (C24)突变属于同一互补群。有两条证据表明en(am)-2是粗糙脉孢菌中谷氨酸合酶的结构基因。en(am)-2+基因对酶活性表现出基因剂量效应，并且一些缺乏谷氨酸合酶活性的突变体具有交叉反应物质。这些数据表明这些突变位于粗糙脉孢菌谷氨酸合酶的结构基因中。
