Zhong Chuanqing, Zhang Peipei, Liu Cheng, Liu Meng, Chen Wenbing, Fu Jiafang, Qi Xiaoyu, Cao Guangxiang
School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, China.
Shandong Medicinal Biotechnology Center, Shandong Academy of Medical Sciences, Shandong First Medical University, Jinan, China.
Front Microbiol. 2019 Sep 13;10:2127. doi: 10.3389/fmicb.2019.02127. eCollection 2019.
NM-1 is a polyphosphate (poly-P)-accumulating bacterium that accumulates poly-P under aerobic conditions and degrades poly-P under anaerobic conditions. In this study, the two-component system (TCS) PolS-PolR was identified in NM-1, and the response regulator PolR was found to directly bind to the promoters of genes related to phosphate transport (MLP_RS00235, MLP_RS23035, and MLP_RS24590); poly-P catabolism (MLP_RS12905) and poly-P synthesis (MLP_RS23025). RT-qPCR assays showed that (MLP_RS12905), ppk (MLP_RS23025), (MLP_RS23035), and (MLP_RS24590) were down-regulated during the aerobic-anaerobic shift. The sequence GTTCACnnnnnGTTCaC was identified as a recognition sequence for PolR by MEME analysis and DNase I footprinting. EMSAs and ChIP-qPCR assays indicated that PolR binds to the promoters of (MLP_RS00235), (MLP_RS12905), (MLP_RS23025), (MLP_RS23035) and (MLP_RS24590), and ChIP-qPCR further suggested that the binding affinity of PolR was lower under anaerobic conditions than under aerobic conditions . These findings indicate that the PolS-PolR TCS in may be involved in the regulation of poly-P metabolism in response to levels of dissolved oxygen in the environment, and our results provide insights into new approaches for understanding the mechanisms of phosphorus accumulation and release.
NM-1是一种聚磷酸盐（poly-P）积累细菌，在有氧条件下积累聚-P，在厌氧条件下降解聚-P。在本研究中，在NM-1中鉴定出双组分系统（TCS）PolS-PolR，发现响应调节因子PolR直接结合到与磷酸盐转运（MLP_RS00235、MLP_RS23035和MLP_RS24590）、聚-P分解代谢（MLP_RS12905）和聚-P合成（MLP_RS23025）相关基因的启动子上。RT-qPCR分析表明，在有氧-厌氧转变过程中，（MLP_RS12905）、ppk（MLP_RS23025）、（MLP_RS23035）和（MLP_RS24590）表达下调。通过MEME分析和DNase I足迹法鉴定出序列GTTCACnnnnnGTTCaC为PolR的识别序列。电泳迁移率变动分析（EMSA）和染色质免疫沉淀定量PCR（ChIP-qPCR）分析表明，PolR结合到（MLP_RS00235）、（MLP_RS12905）、（MLP_RS23025）、（MLP_RS23035）和（MLP_RS24590）的启动子上，ChIP-qPCR进一步表明，PolR在厌氧条件下的结合亲和力低于有氧条件下。这些发现表明，NM-1中的PolS-PolR TCS可能参与响应环境中溶解氧水平对聚-P代谢的调节，我们的结果为理解磷积累和释放机制的新方法提供了见解。
