College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China; Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences (CAS), Shanghai, 200032, China.
College of Bioengineering, Henan University of Technology, Zhengzhou, 450001, China.
Microbiol Res. 2020 Mar;233:126411. doi: 10.1016/j.micres.2020.126411. Epub 2020 Jan 14.
In Streptomyces pristinaespiralis, the orphan histidine kinase (HK) PdtaS-p (encoded by SSDG_02492), which belongs to proteins of two-component systems (TCSs), plays an important role in both morphological differentiation and antibiotic biosynthesis. Owing to the isolated genetic organization of pdtaS-p, it is a challenge to identify its cognate response regulator (RR) and hampers the efforts to elucidate the regulation mechanism of PdtaS-p. In this study, based on bioinformatics analysis, we identify the cognate RR PdtaR-p (encoded by SSDG_04087) of PdtaS-p by phenotype similarity of gene deletion mutants as well as in vitro phosphor-transfer assay. We show that the mutants (ΔpdtaR-p and ΔpdtaS-p) exhibit almost the same phenotypical changes, showing a bald phenotype on MS agar and reduced pristinamycin biosynthesis. Further phosphor-transfer assay indicates that the phosphoryl group of HK PdtaS-p can be specifically transferred to RR PdtaR-p. Compared with the majority of RRs that harbor DNA-binding domains, PdtaR-p contains a putative ANTAR RNA-binding domain involved in controlling gene expression at the post-transcription level. Finally, we demonstrate that their ortholog from the model strain Streptomyces coelicolor, PdtaS-c/PdtaR-c, also regulates both morphological differentiation and antibiotics biosynthesis, suggesting that PdtaS-p/PdtaR-p-mediated molecular regulation may be conserved in the genus Streptomyces. To our knowledge, this is the first report describing the functional identification of ANTAR RNA-binding regulators in Streptomyces.
在吸水链霉菌中，孤儿组氨酸激酶（HK）PdtaS-p（由 SSDG_02492 编码），属于双组分系统（TCS）的蛋白质，在形态分化和抗生素生物合成中都起着重要作用。由于 pdtaS-p 的遗传组织是孤立的，因此识别其同源反应调节剂（RR）具有挑战性，并阻碍了阐明 PdtaS-p 调节机制的努力。在这项研究中，基于生物信息学分析，我们通过基因缺失突变体的表型相似性以及体外磷转移实验鉴定了 PdtaS-p 的同源 RR PdtaR-p（由 SSDG_04087 编码）。我们表明，突变体（ΔpdtaR-p 和 ΔpdtaS-p）表现出几乎相同的表型变化，在 MS 琼脂上表现出光秃的表型，并且普鲁兰霉素生物合成减少。进一步的磷转移实验表明，HK PdtaS-p 的磷酸基团可以特异性地转移到 RR PdtaR-p 上。与大多数含有 DNA 结合结构域的 RR 相比，PdtaR-p 包含一个假定的 ANTAR RNA 结合结构域，涉及在转录后水平控制基因表达。最后，我们证明来自模式菌株变铅青链霉菌的同源物 PdtaS-c/PdtaR-c 也调节形态分化和抗生素生物合成，表明 PdtaS-p/PdtaR-p 介导的分子调节可能在吸水链霉菌属中保守。据我们所知，这是第一个描述吸水链霉菌中 ANTAR RNA 结合调节因子的功能鉴定的报告。
