Phages counteract bacterial immunity in myriad ways – Nassos Typas

We invite everyone to come to our extra CMFI seminar/Joint Microbiology Colloquium. This time, there will be just one very exciting talk. Afterwards, we will have a little get-together with coffee and snacks.

Time: October 23rd, 2:30pm

Place: M3 seminar room

Speaker: Nassos Typas, EMBL Heidelberg

Host: Lisa Maier, CMFI

Talk title and abstract below.

Phages counteract bacterial immunity in myriad ways

The foundations of molecular biology have been established in the mid of the 20^th century by studying bacteriophages. Restriction-modification systems and CRISPR, tools that have propelled genetic engineering, are systems that bacteria use to defend against phage attack. Yet, only recently have we started to understand how extensive and molecularly diverse are interactions between bacteria and phages. Hundreds of new bacterial immunity systems have been identified in the past few years, many forming the origins of eukaryotic innate immunity systems. How those systems sense phage attack and act is still poorly understood. Even less understood is how phages manage to circumvent them, and how versatile is their arsenal in this perennial warfare and coexistence between bacteria and phages.

Our work builds on our recent discovery that the enigmatic bacterial retrons, the first prokaryotic elements discovered to encode a reverse transcriptase, serve actually as phage defense systems. First, I will show how a functional metagenomics approach enabled us to discover dozens of diverse small phage proteins that block the toxic activity of a specific retron, and how evolution has found numerous convergent ways to solve the same problem. Then I will present how phages use rampant phosphorylation to broadly counteract diverse bacterial innate immunity systems.