Previous studies have identified TnpB proteins with inactivated nuclease domains, termed TnpB-like nuclease-dead repressors (TldRs) that do not function in transposition.
Although the previous study reported that FliC P -associated TldRs repress host flagellin gene expression and remodel flagella with the phage-encoded flagellin, the functional relevance of this regulation for host fitness was elusive.
The authors next showed that the Flagellin Remodeling phage (FRφ) is a temperate phage that produces Siphoviridae-like virions.
Moreover, they found that phage infection led to the complete switch in filament composition from FliC H to FliC P .
Further experiments revealed that FRφ infection does not require flagella and that the phage uses the β-barrel outer membrane receptor FhuA for entry.
Transposon-encoded TnpB proteins are RNA-guided nucleases that use a transposon-encoded guide RNA to cleave DNA target sequences, promoting the maintenance, propagation and mobility of associated transposable elements within host genomes. Previous studies have identified TnpB proteins with inactivated nuclease domains, termed TnpB-like nuclease-dead repressors (TldRs) that do not function in transposition. Instead, they have been shown to exert RNA-guided transcriptional control: the non-coding guide RNAs target cDNA sequences within promoter regions or 5′ untranslated regions, leading to the downregulation of gene expression. Moreover, it was also shown that the TldR–guide RNA cassette associates with a gene encoding a novel flagellin isoform (FliC P ), which is the extracellular subunit of the bacterial flagellum, and that all these genes are encoded within a prophage. Although the previous study reported that FliC P -associated TldRs repress host flagellin gene expression and remodel flagella with the phage-encoded flagellin, the functional relevance of this regulation for host fitness was elusive. In this new study, Walker, Richard et al. report that phage-mediated flagellin remodelling enhances bacterial motility, mammalian immune evasion and host colonization.
The authors next showed that the Flagellin Remodeling phage (FRφ) is a temperate phage that produces Siphoviridae-like virions. Moreover, they found that phage infection led to the complete switch in filament composition from FliC H to FliC P . Further experiments revealed that FRφ infection does not require flagella and that the phage uses the β-barrel outer membrane receptor FhuA for entry.
