Chou C F, Chen C W
Institute of Microbiology and Immunology, National Yang-Ming Medical College, Taiwan, R.O.C.
Biochem Biophys Res Commun. 1992 Dec 15;189(2):1101-9. doi: 10.1016/0006-291x(92)92318-r.
Spontaneous Arg- mutants arose at high frequencies in Streptomyces lividans. Exposure to ethidium bromide increased the frequency of arg instability. In Pro+ strains the induced arg mutants were mainly argG, but in the proB mutants, a new mutation, argJ, prevailed which lacked ornithine acetyltransferase activity and required ornithine for growth. Introduction of the cloned proB gene of Streptomyces coelicolor A3(2) into the proB argJ mutants not only complemented the proB mutation but also suppressed the argJ mutation. The proB mutation was also suppressed by adding ornithine to the medium. These results indicated crossfeeding(s) between the arginine and proline pathways in S. lividans, which presumably circumvented the detection of argJ mutations in Pro+ strains.
自发的精氨酸突变体在淡紫链霉菌中高频出现。用溴化乙锭处理会增加精氨酸不稳定性的频率。在脯氨酸合成能力正常（Pro⁺）的菌株中，诱导产生的精氨酸突变体主要是argG，但在proB突变体中，一种新的突变argJ占主导，该突变体缺乏鸟氨酸乙酰转移酶活性，生长需要鸟氨酸。将天蓝色链霉菌A3(2)的克隆proB基因导入proB argJ突变体中，不仅互补了proB突变，还抑制了argJ突变。向培养基中添加鸟氨酸也能抑制proB突变。这些结果表明淡紫链霉菌中精氨酸和脯氨酸途径之间存在交叉营养作用，这可能规避了在Pro⁺菌株中对argJ突变的检测。
