Frank Englert     email
Helmholtz Institute for RNA-based Infection Research (HIRI)

Prof. Dr. Chase Beisel (Würzburg)
Promotion Committee:
Prof. Dr. Chase Beisel (Würzburg)
Jun.-Prof. Dr. Alexander Westermann
Dr. Ana Rita Brochado (Würzburg)
Dr. Franziska Faber (Würzburg)

Characterizing novel defense systems in bacteria


Bacteria and phages are embroiled in a perpetual arms race, which has resulted in the evolution of a broad arsenal of defense mechanisms bacteria use to fend of infections by viruses. These defense systems include CRISPR-Cas and restriction-modification systemswhich were proven to be valuable tools for biotechnological applications. In recent years, development of new bioinformatic methods combined with the increased abundance of metagenomic data, has uncovered a large variety of previously unknown anti-phage defense systems in bacteria. These exhibit both familiar mechanisms, like toxin-antitoxins and abortive infections, but also novel mechanisms like nucleotide exclusion systems.

My work focuses on two of these novel anti-phage defense systems: The first system, called Thoeris, incorporates TIR-like domains, similar to signal-transducing components of animal and plant immune receptors. After infection by an invading pathogen is recognized, the system induces growth arrest and cell death to prevent the phage from propagating, thereby protecting the surrounding bacterial community.

The second system, called Zorya, is much less characterized so far. Like for Thoeris, phage infection triggers an abortive infection and killing the cell, but the exact mechanism remains unclear. The goal of my work is to uncover how the systems recognize phage infections, the mechanisms that result in the cell death, as well as countermeasures phages might employ to circumvent the systems.