Luzhetskiĭ A N, Ostash B E, Fedorenko V A
Department Genetics and Biotechnology, Ivan Franko National University of Lviv, 79005 Ukraine.
Genetika. 2001 Oct;37(10):1340-7.
Streptomyces globisporus 1912 produces a novel angucycline antitumor antibiotic landomycin E (LE). To study the LE biosynthetic gene cluster in detail, a system for the conjugal transfer of the integrative plasmid pSET152 from Escherichia coli into S. globisporus 1912 has been developed. It was shown that this plasmid integrates into two sites of the S. globisporus chromosome and is stably inherited under nonselective conditions. pSET152+ exconjugants of the strain 1912 are characterized by a significant decrease in LE synthesis (by 50-90%). A negative effect of pSET152 integration on antibiotic production was observed even upon the use of the recipient strain with increased LE synthesis, although in this case, the level of LE production in ex-conjugants was 120-150% of that in the original strain 1912. Based on pSET152, a vector system for gene knockouts in S. globisporus was developed. The effectivity of this system was shown in the example of disruption of the lndA gene encoding the key enzyme of LE synthesis (beta-ketoacylsynthase). Inactivation of this gene was shown to lead to the cessation of LE biosynthesis.
球形孢链霉菌1912产生一种新型的安古霉素类抗肿瘤抗生素地霉素E（LE）。为了详细研究LE生物合成基因簇，已开发出一种将整合质粒pSET152从大肠杆菌接合转移至球形孢链霉菌1912的系统。结果表明，该质粒整合到球形孢链霉菌染色体的两个位点，并且在非选择性条件下能稳定遗传。1912菌株的pSET152 + 接合子的特征是LE合成显著减少（减少50 - 90%）。即使使用LE合成增加的受体菌株，也观察到pSET152整合对抗生素生产有负面影响，尽管在这种情况下，接合子中LE的产量水平是原始菌株1912的120 - 150%。基于pSET152，开发了一种用于球形孢链霉菌基因敲除的载体系统。以编码LE合成关键酶（β - 酮酰基合成酶）的lndA基因的破坏为例，展示了该系统的有效性。该基因的失活导致LE生物合成停止。
