MilR2, a novel TetR family regulator involved in 5-oxomilbemycin A3/A4 biosynthesis in Streptomyces hygroscopicus
MilR2, a novel TetR family regulator involved in 5-oxomilbemycin A3/A4 biosynthesis in Streptomyces hygroscopicus
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MilR2，一种新型 TetR 家族调节因子，参与吸水链霉菌 5-oxomilbmycin A3/A4 生物合成
DOI：
10.1007/s00253-018-9280-2
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发表时间：
2018-08
影响因子：
5
通讯作者：
Chen Shaoxin
中科院分区：
文献类型：
--
作者：
Wei Keke;Wu Yuanjie;Li Lei;Jiang Weihong;Hu Jinfeng;Lu Yinhua;Chen Shaoxin
米尔贝霉素由多种链霉菌产生，是一组 16 元大环内酯类化合物，具有有效的杀虫和驱虫活性。米尔贝霉素A3/A4是米尔贝霉素生物合成途径的主要成分，而5-oxomilbmycin A3/A4是未还原C-5酮基的米尔贝霉素A3/A4的类似物，已被开发为杀螨剂、杀虫剂和驱虫剂。然而，迄今为止，人们对米尔倍霉素生物合成的调控知之甚少，这极大地阻碍了通过代谢工程产生高产菌株。在此，鉴定出 TetR 家族调节因子 MilR2（由 sbi_00792 编码）参与 5-oxomibemycin 高产菌株吸水链霉菌 SIPI-KF 中 5-oxomibemycin A3/A4 生物合成的激活。具有 MilR2 DNA 结合域框内删除的 ΔmilR2 突变体导致在测试的两个时间点显着降低 5-oxomibemycin A3/A4 产量（约 36.9 和 39.7%），因此将 milR2 的额外拷贝引入 SIPI-KF 导致产量增加 12.6 和 34.4%。我们进一步表明，MilR2 可以直接抑制编码假定水解酶的基因 sbi_00791 的转录，该基因与 milR2 的位置不同。定义了精确的 MilR2 结合位点，该位点由 10-nt 分隔的 7-nt 完美反向重复序列 (5'-ACCAACCAGCTGGTAAGGGTTGGT-3') 组成。 MilR2结合位点的原位诱变导致5-oxomibemycin A3/A4产量减少19.7%和13.5%，远低于ΔmilR2的减少率。总的来说，结果表明 MilR2 作为 5-oxomibemycin A3/A4 产生的激活剂，并且 MilR2 的功能仅部分通过其对 sbi_00791 转录的抑制来介导。
Milbemycins produced by several Streptomyces species are a group of 16-membered macrolides with potent insecticidal and anthelminthic activity. Milbemycin A3/A4, the main components of the milbemycins biosynthetic pathway, and 5-oxomilbemycin A3/A4, the analogs of milbemycin A3/A4 without the reduction of the C-5 keto group, have been developed as acaricides, insecticides, and anthelmintics. However, so far, little is known about the regulation of milbemycins biosynthesis, which has greatly hampered the generation of high producing strains by metabolic engineering. Herein, a TetR family regulator MilR2 (encoded by sbi_00792) was identified being involved in activation of 5-oxomilbemycin A3/A4 biosynthesis in a high 5-oxomilbemycins-producing strain Streptomyces hygroscopicus SIPI-KF. The ΔmilR2 mutant with an in-frame deletion of the MilR2 DNA-binding domain resulted in significantly reduced 5-oxomilbemycin A3/A4 production (approximately 36.9 and 39.7%) at tested two time points, and accordingly introduction of an extra copy of milR2 into SIPI-KF led to enhanced production by 12.6 and 34.4%. We further showed that MilR2 could directly repress the transcription of the gene sbi_00791 encoding a putative hydrolase, which is located divergently from milR2. The precise MilR2-binding site consisting of a 7-nt perfect inverted repeat separated by 10-nt (5′-ACCAACCAGCTGGTAAGGGTTGGT-3′) was defined. In situ mutagenesis of the MilR2-binding site resulted in 19.7 and 13.5% decreases in 5-oxomilbemycin A3/A4 production, which is much lower than the decreased rates of ΔmilR2. Collectively, the results demonstrated that MilR2 serves as an activator for 5-oxomilbemycin A3/A4 production and the function of MilR2 is only partially mediated through its repression on the transcription of sbi_00791.
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影响因子：
1.2
作者：
C. Wilkinson;Z. Hughes-Thomas;Christine J. Martin;I. Böhm;T. Mironenko;M. Deacon;M. Wheatcroft;G. Wirtz;J. Staunton;P. Leadlay
通讯作者：
C. Wilkinson;Z. Hughes-Thomas;Christine J. Martin;I. Böhm;T. Mironenko;M. Deacon;M. Wheatcroft;G. Wirtz;J. Staunton;P. Leadlay
影响因子：
4.9
作者：
BURG, RW;MILLER, BM;OMURA, S
通讯作者：
OMURA, S
影响因子：
3.1
作者：
Xiangjing Wang;Bo Zhang;Yi-Jun Yan;Jing An;Ji Zhang;Chongxi Liu;W. Xiang
通讯作者：
Xiangjing Wang;Bo Zhang;Yi-Jun Yan;Jing An;Ji Zhang;Chongxi Liu;W. Xiang
影响因子：
5
作者：
Ji Zhang;Jing An;Ji-Jia Wang;Yi-Jun Yan;Hai-Rong He;Xiang-Jing Wang;Wen-Sheng Xiang
通讯作者：
Ji Zhang;Jing An;Ji-Jia Wang;Yi-Jun Yan;Hai-Rong He;Xiang-Jing Wang;Wen-Sheng Xiang
影响因子：
6.4
作者：
Kim MS;Cho WJ;Song MC;Park SW;Kim K;Kim E;Lee N;Nam SJ;Oh KH;Yoon YJ
通讯作者：
Yoon YJ