| Autor: |
Zhuo L; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China., Wan TY; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China., Pan Z; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China., Wang JN; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China., Sheng DH; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China., Li YZ; State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong Universitygrid.27255.37, Qingdao, People's Republic of China. |
| Abstrakt: |
Differential transcription of functionally divergent duplicate genes is critical for bacterial cells to properly and competitively function in the environment, but the transcriptional regulation mechanisms remain in mystery. Myxococcus xanthus DK1622 possesses two duplicate groEL s with divergent functions. Here, we report that MXAN_4468 , an orphan gene located upstream of groEL2 , encodes a response regulator (RR) and is responsible for the differential expression regulation of duplicate groEL s. This RR protein realizes its negative regulatory role via a novel dual-mode functioning manner: binding to the transcription repressor HrcA to enhance its transcriptional inhibition of duplicate groEL s and binding to the 3' end of the MXAN_4468 sequence to specifically decrease the transcription of the following groEL2 . Phosphorylation at the conserved 61 st aspartic acid is required to trigger the regulatory functions of MXAN_4468. Pull-down experiment and mutation demonstrated that two noncognate CheA proteins, respectively belonging to the Che8 and Che7 chemosensory pathways, are involved in the protein phosphorylation. A transcriptome analysis, as well as the pull-down experiment, suggested that MXAN_4468 plays a global negative regulatory role in M. xanthus. This study elucidates, for the first time, the regulatory mechanism of differential transcription of bacterial duplicate groEL s and suggests a global regulatory role of a dual-functional orphan RR. IMPORTANCE Multiply copied groEL s require precise regulation of transcriptions for their divergent cellular functions. Here, we reported that an orphan response regulator (RR) tunes the transcriptional discrepancy of the duplicate groEL s in Myxococcus xanthus DK1622 in a dual-functional mode. This RR protein has a conserved phosphorylation site, and the phosphorylation is required for the regulatory functions. Transcriptomic analysis, as well as a pull-down experiment, suggests that the RR plays a global regulatory role in M. xanthus. This study highlights that the dual-functional orphan RR might be involved in conducting the transcriptional symphony to stabilize the complex biological functions in cells. |
