Vetrivel K S, Dharmalingam K
Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, India.
Can J Microbiol. 2000 Oct;46(10):956-60.
Streptomyces peucetius, producer of the antitumor anthracycline antibiotic daunorubicin, was mutagenized, and mutants defective in daunorubicin biosynthesis were screened. One mutant (SPVI), which failed to produce daunorubicin, was found to overproduce an extracellular chitinase. Time course analyses of chitinase production and of the extracellular protein profile showed that the increase in activity is due to increased synthesis of the enzyme protein. The production of chitinase in SPVI was repressed by glucose as in the case of wild-type S. peucetius. PFGE analysis of VspI restriction fragments of S. peucetius and SPVI showed that there was no major alteration in the mutant genome. The hybridization pattern of S. peucetius and SPVI genomic DNA digested with various restriction enzymes was identical when probed with dnrUVJI genes of the S. peucetius daunorubicin cluster and chiA of Streptomyces lividans 66. The possible step affected in the daunorubicin biosynthetic pathway could be a polyketide synthase, since aklanonic acid, the earliest detectable intermediate in the daunorubicin pathway, was not synthesized in SPVI.
抗肿瘤蒽环类抗生素柔红霉素的产生菌变铅青链霉菌经诱变处理后，筛选柔红霉素生物合成缺陷的突变体。发现一株不产生柔红霉素的突变体（SPVI）过量产生一种胞外几丁质酶。几丁质酶产生及胞外蛋白质谱的时间进程分析表明，活性增加是由于酶蛋白合成增加所致。与野生型变铅青链霉菌一样，SPVI中几丁质酶的产生受葡萄糖抑制。对变铅青链霉菌和SPVI的VspI酶切片段进行脉冲场凝胶电泳（PFGE）分析表明，突变体基因组无重大改变。用变铅青链霉菌柔红霉素基因簇的dnrUVJI基因及天蓝色链霉菌66的chiA作为探针时，经各种限制酶消化的变铅青链霉菌和SPVI基因组DNA的杂交图谱相同。柔红霉素生物合成途径中可能受影响的步骤可能是聚酮合酶，因为在SPVI中不合成柔红霉素途径中最早可检测到的中间体阿克拉农酸。
