Monday, March 11, 2019

BacterioFiles 377 - Distributed Defense-Defeating Devices

This episode: Newly discovered CRISPR-inhibiting genes are found in many different bacterial groups!

Download Episode (8.0 MB, 8.8 minutes)

Show notes:
Microbe of the episode: Borrelia mazzottii

News item

The discovery of the microbial immune system, CRISPR-Cas, changed many things about the way we think of microbial ecology and interactions with microbe-infecting viruses. The CRISPR-Cas system can learn to detect new threats by capturing bits of their genetic sequences and using these to target the Cas proteins to chop up any such sequences that make it into the cytoplasm. This can greatly increase microbial survival in certain ecosystems in which viruses regularly kill a large percentage of the microbial population.

To overcome this defense, a virus has to adapt, either by acquiring mutations that change its sequence, thus escaping detection, or by acquiring anti-CRISPR proteins that shut down the microbial defense directly. These possibilities make the complex ecology even more interesting.

In this study, scientists develop a clever method for screening for new anti-CRISPR genes, and go searching for them in samples from various places (soil, animal guts, human gut). They find several new examples, which turn out to be found in many different kinds of species in many different environments.

Journal Paper:
Uribe RV, Helm E van der, Misiakou M-A, Lee S-W, Kol S, Sommer MOA. 2019. Discovery and Characterization of Cas9 Inhibitors Disseminated across Seven Bacterial Phyla. Cell Host & Microbe 25:233-241.e5.

Other interesting stories:

Post questions or comments here or email to Thanks for listening!

Subscribe: Apple Podcasts, RSS, Google Play. Support the show at Patreon, or check out the show at Twitter or Facebook.

No comments:

Post a Comment