HtrA‐mediated selective degradation of DNA uptake apparatus accelerates termination of pneumococcal transformation. Issue 4 (29th August 2019)

• Record Type: Journal Article
• Authors: Liu, Yanni; Zeng, Yuna; Huang, Yijia; Gu, Lixiao; Wang, Shaolin; Li, Chunhao; Morrison, Donald A.; Deng, Haiteng; Zhang, Jing‐Ren
• Is Part Of: Molecular microbiology. Volume 112:Issue 4(2019)
• Page Start: 1308
• Page End: 1325
• Publication Date: 2019-08-29
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.14364
• Languages: English
• ISSNs: 0950-382X

Abstract

Summary: Natural transformation mediates horizontal gene transfer, and thereby promotes exchange of antibiotic resistance and virulence traits among bacteria. Streptococcus pneumoniae, the first known transformable bacterium, rapidly activates and then terminates the transformation state, but it is unclear how the bacterium accomplishes this rapid turn‐around at the protein level. This work determined the transcriptomic and proteomic dynamics during the window of pneumococcal transformation. RNA sequencing revealed a nearly uniform temporal pattern of rapid transcriptional activation and subsequent shutdown for the genes encoding transformation proteins. In contrast, mass spectrometry analysis showed that the majority of transformation proteins were substantially preserved beyond the window of transformation. However, ComEA and ComEC, major components of the DNA uptake apparatus for transformation, were completely degraded at the end of transformation. Further mutagenesis screening revealed that the membrane‐associated serine protease HtrA mediates selective degradation of ComEA and ComEC, strongly suggesting that breakdown of the DNA uptake apparatus by HtrA is an important mechanism for termination of pneumococcal transformation. Finally, our mutagenesis analysis showed that HtrA inhibits natural transformation of Streptococcus mitis and Streptococcus gordonii . Together, this work has revealed that HtrA regulates the level and duration of natural transformation in multiple streptococcal species. Abstract : In response to the CSP pheromone or antibiotics, pneumococci become competent for genetic transformation by reprograming their transcriptome and proteome to produce the transformation pilus and DNA uptake apparatus for internalizing and recombining foreign DNA into the chromosome. Serine protease HtrA promotes the termination of transformation by mediating selective degradation of ComEA and ComEC, two major components of the DNA uptake apparatus, in the late phase of transformation.