XRE transcription factors conserved in < i > Caulobacter < /i > and φCbK modulate adhesin development and phage production

by Maeve McLaughlin, Aretha Fiebig, Sean Crosson

The xenobiotic response element (XRE) family of transcription factors (TFs), which are commonly encoded by bacteria and bacteriophage, regulate diverse features of bacterial cell physiology and impact phage infection dynamics. Through a pangenome analysis ofCaulobacter species isolated from soil and aquatic ecosystems, we uncovered an apparent radiation of a paralogous XRE TF gene cluster, several of which have established functions in the regulation of holdfast adhesin development and biofilm formation inC.crescentus. We further discovered related XRE TFs throughout the classAlphaproteobacteria and its phages, including the φCbK Caulophage, suggesting that members of this cluster impact host-phage interactions. Here we show that a closely related group of XRE transcription factors encoded by bothC.crescentus and φCbK can physically interact and function to control the transcription of a common gene set, influencing processes including holdfast development and the production of φCbK virions. The φCbK-encoded XRE paralog,tgrL, is highly expressed at the earliest stages of infection and can directly inhibit transcription of host genes includinghfiA, a potent holdfast inhibitor, andgafYZ, an activator of prophage-like gene transfer agents (GTAs). XRE proteins encoded from theC.crescentus chromosome also directly repressgafYZ transcription, revealing a functionally redundant set of host regulators that may protect against spur...

Source: PLoS Genetics - November 16, 2023 Category: Genetics & Stem Cells Authors: Maeve McLaughlin Source Type: research