State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Department of Environmental and Biological Engineering, School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing, 100083, China.
Sci China Life Sci. 2017 Sep;60(9):992-999. doi: 10.1007/s11427-017-9121-4. Epub 2017 Jul 26.
Increasing the self-resistance levels of Streptomyces is an effective strategy to improve the production of antibiotics. To increase the oxytetracycline (OTC) production in Streptomyces rimosus, we investigated the cooperative effect of three co-overexpressing OTC resistance genes: one gene encodes a ribosomal protection protein (otrA) and the other two express efflux proteins (otrB and otrC). Results indicated that combinational overexpression of otrA, otrB, and otrC (MKABC) exerted a synergetic effect. OTC production increased by 179% in the recombinant strain compared with that of the wild-type strain M4018. The resistance level to OTC was increased by approximately two-fold relative to the parental strain, thereby indicating that applying the cooperative effect of self-resistance genes is useful to improve OTC production. Furthermore, the previously identified cluster-situated activator OtcR was overexpressed in MKABC in constructing the recombinant strain MKRABC; such strain can produce OTC of approximately 7.49 g L, which represents an increase of 19% in comparison with that of the OtcR-overexpressing strain alone. Our work showed that the cooperative overexpression of self-resistance genes is a promising strategy to enhance the antibiotics production in Streptomyces.
提高链霉菌的自我抗性水平是提高抗生素产量的有效策略。为了提高弗氏链霉菌中产土霉素（OTC）的产量，我们研究了三种协同过表达 OTC 抗性基因的协同作用：一个基因编码核糖体保护蛋白（otrA），另外两个基因表达外排蛋白（otrB 和 otrC）。结果表明，otrA、otrB 和 otrC 的组合过表达（MKABC）具有协同作用。与野生型菌株 M4018 相比，重组菌株的 OTC 产量增加了 179%。与亲本菌株相比，对 OTC 的抗性水平提高了约两倍，这表明应用自我抗性基因的协同作用有助于提高 OTC 的产量。此外，在构建重组菌株 MKRABC 时，在 MKABC 中过表达了先前鉴定的位于簇中的激活子 OtcR；该菌株可以产生约 7.49 g/L 的 OTC，与单独过表达 OtcR 的菌株相比，产量增加了 19%。我们的工作表明，协同过表达自我抗性基因是提高链霉菌中抗生素产量的一种很有前途的策略。
