Biology subjects

Kotovskaya, O.

Publications and source records attributed to Kotovskaya, O..

2 recordsLinked to original sources

bioRxiv2026

Phages infecting the common gut commensal Escherichia coli HS reveal tropism for its Klebsiella-like capsule

Tailed dsDNA phages are ubiquitous and thought to infect almost any bacterial species. Escherichia coli HS - a commensal strain used as a model in gut colonization studies - has not been reported as a host for dsDNA phages and is resistant to more than 100 coliphages from the BASEL collection. Here, we report the first phages infecting E. coli HS, characterize their interaction with an endogenous BREX system, and provide a detailed genomic and phylogenetic description. Phages {phi}HS1 (Queuovirinae) and {phi}HS2 (Ackermannviridae) possess dPreQ and 5-NeOmdU modifications that confer resistance to restriction digestion. {phi}HS3 is a temperate phage, related to the native HS prophage {phi}HS4, and represents a founding member of a novel genus (Hueyvirus) of P22-like phages capable of lateral transduction. We reveal exchange of tailspike genes between {phi}HS2, {phi}HS3, and Klebsiella-specific phages. Furthermore, we demonstrate that E. coli HS encodes a Klebsiella-like K47 capsule required for phage infection. These results suggest that the broad phage resistance of E. coli HS may be linked to its capsular type.

microbiology↗

bioRxiv2025

A census of anti-CRISPR proteins reveals AcrIE9 as an inhibitor of Escherichia coli K12 Type IE CRISPR-Cas system

CRISPR-Cas adaptive immunity systems provide defense against mobile genetic elements and are often countered by diverse anti-CRISPR (Acr) proteins. The Type IE CRISPR-Cas of Escherichia coli K12 has been a model for structural and functional studies and is a part of the species core genome. However, this system is transcriptionally silent, which has fueled questions about its true biological function. To clarify the role of this system in defense, we carried out a census of Acr proteins found in Enterobacterales and identified AcrIE9 as a potent inhibitor of the E. coli K12 Type IE CRISPR-Cas system. While sharing little sequence identity, AcrIE9 proteins from Pseudomonas and Escherichia both interact with the Cas7 subunit of the Cascade complex, thus preventing its binding to DNA. We further show that AcrIE9 is genetically linked to AcrIE10, forming the most widespread anti-CRISPR cluster in Enterobacterales, and this module often co-occurs with a novel HTH-like protein with unusual architecture.

microbiology↗