Light-inducible carotenoid production controlled by a MarR-type regulator in Corynebacterium glutamicum
Light-inducible carotenoid production controlled by a MarR-type regulator in Corynebacterium glutamicum
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DOI：
10.1038/s41598-019-49384-7
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发表时间：
2019-09
影响因子：
4.6
通讯作者：
Satoru Sumi;Yuto Suzuki;Tetsuro Matsuki;Takahiro Yamamoto;Yudai Tsuruta;K. Mise;T. Kawamura;Yusuke Ito;Yuka Shimada;Erika Watanabe;Shoko Watanabe;Minami Toriyabe;Hatsumi Takano (Shiratori);K. Ueda;H. Takano
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作者：
Satoru Sumi;Yuto Suzuki;Tetsuro Matsuki;Takahiro Yamamoto;Yudai Tsuruta;K. Mise;T. Kawamura;Yusuke Ito;Yuka Shimada;Erika Watanabe;Shoko Watanabe;Minami Toriyabe;Hatsumi Takano (Shiratori);K. Ueda;H. Takano
一些非向光性细菌中的类胡萝卜素生产以光依赖性方式发生，以保护细胞免受光氧化剂的影响。关于非光养细菌光依赖性类胡萝卜素生产中涉及的转录调节因子的知识主要局限于属于 MerR 家族转录调节因子的基于辅酶 B12 的光敏调节因子 CarH/LitR 家族蛋白。在这项研究中，我们发现属于微球菌和棒状杆菌的细菌表现出光依赖性类胡萝卜素样色素的产生，其中包括氨基酸生产者谷氨酸棒杆菌AJ1511。 CrtR 是假定的 MarR 家族转录调节因子，位于这些细菌基因组中类胡萝卜素生物合成基因簇的分歧区域。无效突变体forcrtRofC.glutamicumAJ1511表现出不依赖于光的类胡萝卜素的组成型生产。 crtR突变体的互补菌株以光依赖性方式产生类胡萝卜素。转录分析显示，野生型中类胡萝卜素生物合成基因的表达以光依赖性方式受到调节，而crtR突变体中的转录与光无关。体外实验表明，重组CrtR蛋白与crtR和crtE基因间区域内的特定序列结合，对应于-58至-7 forcrtE，并且 相对于转录起始位点而言，crtR 的+26 至-28，并作为包含SigA 的RNA 聚合酶指导的crtE 转录的阻遏物。总之，结果表明CrtR光依赖性控制谷氨酸棒杆菌和可能密切相关的放线菌中类胡萝卜素基因簇的表达。
Carotenoid production in some non-phototropic bacteria occurs in a light-dependent manner to protect cells from photo-oxidants. Knowledge regarding the transcriptional regulator involved in the light-dependent production of carotenoids of non-phototrophic bacteria has been mainly confined to coenzyme B12-based photo-sensitive regulator CarH/LitR family proteins belonging to a MerR family transcriptional regulator. In this study, we found that bacteria belonging toMicrococcalesandCorynebacterialesexhibit light-dependent carotenoid-like pigment production including an amino acid-producerCorynebacterium glutamicumAJ1511. CrtR is a putative MarR family transcriptional regulator located in the divergent region of a carotenoid biosynthesis gene cluster in the genome of those bacteria. A null mutant forcrtRofC.glutamicumAJ1511 exhibited constitutive production of carotenoids independent of light. A complemented strain of thecrtRmutant produced carotenoids in a light-dependent manner. Transcriptional analysis revealed that the expression of carotenoid biosynthesis genes is regulated in a light-dependent manner in the wild type, while the transcription was upregulated in thecrtRmutant irrespective of light.In vitroexperiments demonstrated that a recombinant CrtR protein binds to the specific sequences within the intergenic region ofcrtRandcrtE, which corresponds to −58 to −7 forcrtE, and +26 to −28 forcrtRwith respect to the transcriptional start site, and serves as a repressor forcrtEtranscription directed by RNA polymerase containing SigA. Taken together, the results indicate that CrtR light-dependently controls the expression of the carotenoid gene cluster inC.glutamicumand probably closely relatedActinobacteria.