Dairy phages escape CRISPR defence of Streptococcus thermophilus via the anti-CRISPR AcrIIA3.

Bacterial community collapse due to phage infection is a major risk in cheese making processes. As virulent phages are ubiquitous and diverse in milk fermentation factories, the use of phage-resistant lactic acid bacteria (LAB) is essential to obtain high-quality fermented dairy products. The LAB species Streptococcus thermophilus contains two type II-A CRISPR-Cas systems (CRISPR1 and CRISPR3) that can effectively protect against phage infection.

Marker-free co-selection for successive rounds of prime editing in human cells.

Prime editing enables the introduction of precise point mutations, small insertions, or short deletions without requiring donor DNA templates. However, efficiency remains a key challenge in a broad range of human cell types. In this work, we design a robust co-selection strategy through coediting of the ubiquitous and essential sodium/potassium pump (Na/K ATPase).