Project description:Staphylococcus phage 812, strain K1/420, is a broad-acting bacteriophage infecting S. aureus. Phage 812 belongs to the family Herelleviridae and is closely related to kayviruses. We conducted a structural study of the viral particle of phage 812 before and after genome ejection. We characterized the protein components forming the particle and described the changes in their structural arrangement that govern genome anchoring, gating, and release.
Project description:We analyzed RNA-Seq data of two Staphylococcus aureus strains, Newman and SH1000, infected by Kayvirus phage K. Staphylococcus virus K is used in the phage therapy, its genome is 148 kb long consisting of dsDNA with long terminal repeats, and encodes 233 ORFs and 4 tRNAs. The sampling times 0, 2, 5, 10, 20, and 30 minutes after infection were chosen based on the growth characteristics of the phage K at the two S. aureus strains. From the RNA-Seq data we determined transcriptional profile of the phage K and its hosts, which allowed us to identify differentially expressed genes, ncRNAs, and promotor and terminator sites. Transcription of the phage K genes starts immediately after the infection of bacterial cells and we found a gradual take-over by phage K transcripts in the infected cells. The temporal transcriptional profile of phage K was similar in both strains and the relative expression of phage K genes shows three distinct transcript types – early, middle, and late based on the time they reach maximum expression. The bacterial response to phage K infection is similar to the general stress response. It includes the upregulation of nucleotide, amino acid and energy synthesis and transporter genes and the downregulation of transcription factors. The expression of particular virulence genes involved in adhesion and immune system evasion as well as prophage integrases were marginally affected. This work unveils the versatile nature of phage K infection leading to its broad host range