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bioRxiv · 10.1101/2019.12.16.877910

Separating Functions of the Phage-Encoded Quorum-Sensing-Activated Antirepressor Qtip

Silpe, J. E.·Bridges, A. A.·Huang, X.·Coronado, D. R.·Duddy, O. P.·Bassler, B. L.
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Abstract

Quorum sensing is a process of chemical communication that bacteria use to track cell density and coordinate gene expression across a population. Bacteria-infecting viruses, called phages, can encode quorum-sensing components that enable them to integrate host cell density information into the lysis-lysogeny decision. Vibriophage VP882 is one such phage, and activation of its quorum-sensing pathway leads to the production of an antirepressor called Qtip. Qtip interferes with the prophage repressor (cIVP882), leading to host-cell lysis. Here, we show that Qtip interacts with the N-terminus of cIVP882, inhibiting both cIVP882 DNA-binding and cIVP882 autoproteolysis. Qtip also sequesters cIVP882, localizing it to the poles. Qtip can localize to the poles independently of cIVP882. Alanine-scanning mutagenesis of Qtip shows that its localization and interference with cIVP882 activities are separable. Comparison of Qtip to a canonical phage antirepressor reveals that, despite both proteins interacting with their partner repressors, only Qtip drives polar localization.

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Silpe, J. E., Bridges, A. A., Huang, X., Coronado, D. R., Duddy, O. P., Bassler, B. L.. 2019-12-17. Separating Functions of the Phage-Encoded Quorum-Sensing-Activated Antirepressor Qtip. https://doi.org/10.1101/2019.12.16.877910

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