Transcriptional Landscape of Staphylococcus aureus Kayvirus Bacteriophage vB_SauM-515A1

Abstract

The Twort-like myoviruses (Kayvirus genus) of S. aureus are promising agents for bacteriophage therapy due to a broad host range and high killing activity against clinical isolates. This work improves the current understanding of the phage infection physiology by transcriptome analysis. The expression profiles of a typical member of the Kayvirus genus (vB_SauM-515A1) were obtained at three time-points post-infection using RNA sequencing. A total of 35 transcription units comprising 238 ORFs were established. The sequences for 58 early and 12 late promoters were identified in the phage genome. The early promoters represent the strong sigma-70 promoters consensus sequence and control the host-dependent expression of 26 transcription units (81% of genes). The late promoters exclusively controlled the expression of four transcription units, while the transcription of the other five units was directed by both types of promoters. The characteristic features of late promoters were long -10 box of TGTTATATTA consensus sequence and the absence of -35 boxes. The data obtained are also of general interest, demonstrating a strategy of the phage genome expression with a broad overlap of the early and late transcription phases without any middle transcription, which is unusual for the large phage genomes (>100 kbp).

Global Transcriptomic Response of Staphylococcus aureus to Virulent Bacteriophage Infection

“…After incubation at 37 • C for 7 min to allow adsorption, the mixture was centrifuged for 3 min at 10,000× g. The infected bacterial pellet was resuspended in 10 mL of the LB broth. The aliquots (10 µL) were sampled periodically at 0, 5,15,20,25,30,40,50,60, and 70 min, where the 0 min point corresponded to the initial infection of the culture with the bacteriophage from the start of infection. Samples were treated with 2% chloroform.…”

“…However, the plating of infected cells showed a significant decrease in the number of CFUs throughout the entire infection period (Figure 1C). (A) The one-step growth curve of vB_SauM-515A1 bacteriophage, modified from [25]. (B,C) Growth inhibition curves of SA515 strain by the vB_SauM-515A1 phage.…”

Finding functional associations between prokaryotic virus orthologous groups: a proof of concept

“…Second, additional meaningful guilt-by-association features may be included into the predictor (Table 1 ). For example, gene co-expression provides a strong functional signal that is complementary to the genomic signals included here [ 33 , 34 ]. Third, the use of a larger reference set of viral genomes should also be beneficial, as it will better reflect any genomic signals that link interacting phage proteins.…”

Insights into Gene Transcriptional Regulation of Kayvirus Bacteriophages Obtained from Therapeutic Mixtures

“…Morphologically, they are characterized by an isometric head and a long contractile tail (170–220 nm). Their average genome size is about 130 kbp, featuring a pair of long direct repeats at their ends, up to several-thousand bases in length [ 15 ]. Most phages from this genus utilize the backbone of teichoic acid, a ubiquitous molecule associated with the cell wall of Staphylococcus , as their host cell receptor [ 16 ].…”