Two Distinct Modes of Lysis Regulation in Campylobacter Fletchervirus and Firehammervirus Phages

Viruses

Yves Briers¹  MartineCamilla Holst Sørensen²  Lone Brøndsted²  Athina Zampara²  StephenJ. Ahern² 

[1] Department of Biotechnology, Ghent University, Valentin Vaerwijckweg 1, 9000 Gent, Belgium;Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Denmark;

关键词: Campylobacter phages;    lysis regulation;    endolysins;    lysis inhibitor;   

DOI  :  10.3390/v12111247

来源: DOAJ

【 摘 要 】

Campylobacter phages are divided into two genera; Fletchervirus and Firehammervirus, showing only limited intergenus homology. Here, we aim to identify the lytic genes of both genera using two representative phages (F352 and F379) from our collection. We performed a detailed in silico analysis searching for conserved protein domains and found that the predicted lytic genes are not organized into lysis cassettes but are conserved within each genus. To verify the function of selected lytic genes, the proteins were expressed in E. coli, followed by lytic assays. Our results show that Fletchervirus phages encode a typical signal peptide (SP) endolysin dependent on the Sec-pathway for translocation and a holin for activation. In contrast, Firehammervirus phages encode a novel endolysin that does not belong to currently described endolysin groups. This endolysin also uses the Sec-pathway for translocation but induces lysis of E. coli after overexpression. Interestingly, co-expression of this endolysin with an overlapping gene delayed and limited cell lysis, suggesting that this gene functions as a lysis inhibitor. These results indicate that Firehammervirus phages regulate lysis timing by a yet undescribed mechanism. In conclusion, we found that the two Campylobacter phage genera control lysis by two distinct mechanisms.

【 授权许可】

Unknown