CrfP, a fratricide protein, contributes to natural transformation in Streptococcus suis

Abstract

Streptococcussuis (S.suis) is an important zoonotic pathogen that causes septicaemia, meningitis and streptococcal toxic shock-like syndrome in its host, and recent studies have shown that S.suis could be competent for natural genetic transformation. Transformation is an important mechanism for the horizontal transfer of DNA, but some elements that affect the transformation process need to be further explored. Upon entering the competent state, Streptococcus species stimulate the transcription of competence-related genes that are responsible for exogenous DNA binding, uptake and processing. In this study, we performed conserved promoter motif and qRT-PCR analyses and identified CrfP as a novel murein hydrolase that is widespread in S.suis and stimulated with a peptide pheromone in the competent state through a process controlled by ComX. A bioinformatics analysis revealed that CrfP consists of a CHAP hydrolase domain and two bacterial Src homology 3-binding (SH3b) domains. Further characterization showed that CrfP could be exported to extracellular bacterial cells and lytic S.suis strains of different serotypes, and this finding was verified by TEM and a turbidity assay. To investigate the potential effect of CrfP in vivo, a gene-deletion mutant (ΔcrfP) was constructed. Instead of stopping the natural transformation process, the inactivation of CrfP clearly reduced the effective transformation rate. Overall, these findings provide evidence showing that CrfP is important for S.suis serovar 2 competence.

Klebsiella pneumoniae peptide hijacks a Streptococcus pneumoniae permease to subvert pneumococcal growth and colonization

“…One study found that deletion of CbpD reduced transformation efficiency in Streptococcus thermophilus 42 . The same has been observed in Streptococcus sanguinis lacking LytF 43 and Streptococcus suis , lacking CrfP 44 , which are both functional analogues of CbpD.…”

Update on the Mechanisms of Antibiotic Resistance and the Mobile Resistome in the Emerging Zoonotic Pathogen Streptococcus suis

“…After entry into the cells, foreign DNA is taken over by DNA-binding proteins and the homologous recombination system. A fratricidal protein called CrfP regulated by ComR and ComX has been described recently in S. suis [ 70 ]. This protein is an exported murein hydrolase composed of one N-terminal CHAP domain capable of lysing the target cell and two SH3b domains capable of recognizing and binding the cell wall of S. suis .…”

“…This protein is an exported murein hydrolase composed of one N-terminal CHAP domain capable of lysing the target cell and two SH3b domains capable of recognizing and binding the cell wall of S. suis . Inactivation of this protein reduced the transformation rate [ 70 ]. The biological function of CrfP is likely to lyse and release DNA from related Streptococcus strains to provide homologous DNA to competent recipient cells.…”

BlpC-mediated selfish program leads to rapid loss of Streptococcus pneumoniae clonal diversity during infection

“…While our current study was focused on Spn , we hypothesize that other bacteria may employ similar bet-hedging strategies during infection. It is now increasingly appreciated that various bacterial species routinely employ intra- and inter-strain predation to perpetuate their own survival (Arenas et al, 2015; Bushin et al, 2020; González-Pastor et al, 2003; Jamet et al, 2015; Zhu et al, 2021). Both quorum sensing and bacteriocin production are behaviors commonly exhibited by microbes.…”