| Autor: |
Xiao S; Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China., Suo W; Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China., Zhang J; Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China., Zhang X; Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China., Yin Y; Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, People's Republic of China., Guo X; Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China., Zheng Y; Department of Medicine Laboratory, Children's Hospital of Chongqing Medical University; National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders; and Chongqing Key Laboratory of Pediatrics, Chongqing, People's Republic of China. |
| Abstrakt: |
Global transcriptional regulators are prevalent in gram-positive pathogens. The transcriptional regulators of the Mga/AtxA family regulate target gene expression by directly binding to the promoter regions, that results in the coordinated expression of virulence factors. The spd_1587 gene of Streptococcus pneumoniae strain D39 encodes Mga Spn , which shares sequence similarity with global transcriptional regulators of the Mga/AtxA family. In this study, we demonstrated that Mga Spn regulates the biosynthesis of the capsule and phosphorylcholine, which play key roles in disease severity in S. pneumoniae infections. Mga Spn directly binds to the cps and lic1 promoters and affects the biosynthesis of the capsule and phosphorylcholine. Mga Spn binds to two specific sites on the promoter of cps , one of which contains the -35 box of the promoter, with high affinity. Consistently, low-molecular-weight capsule components were observed in the mgaSpn- null mutant strain. Moreover, we found that phosphorylcholine content was notably increased in the unencapsulated mgaSpn mutant strain. The mgaSpn null mutant caused more severe systemic disease than the parental strain D39. These findings indicate that the pneumococcal Mga Spn protein can inhibit capsule and phosphorylcholine production, thereby affecting the virulence of S. pneumoniae. |
