A noncontiguous code for RNA-guided DNA recognition at the origin of CRISPR-Cas.

A tRNA-derived second messenger mediates antiviral defense

CRISPR-Cas systems are RNA-guided nucleases that enable prokaryotic immunity; however, some loci encode additional associated genes that cooperate with CRISPR effectors to perform diverse biological functions. Here, we uncover a CRISPR-associated kinase (CASK) system that links the recognition of target RNA to protein...

VIPR RNA-guided DNA recognition by noncontiguous geometric triplex formation.

When Homing Endonuclease Meets Transposon: The OMEGA System

This article will focus on the selfish behavior of classical homing endonucleases and the OMEGA system, and discuss how it has evolved, been maintained, and adapted to new genomic environments.

Engineering TnpB as a compact RNA-guided genome editor from molecular constraints to design principles

Recent discoveries of non-CRISPR RNA-guided nucleases have expanded the landscape of programmable genome editing beyond canonical Cas systems. Among these, TnpB proteins derived from IS200/IS605-family transposable elements are ultra-compact RNA-guided DNA endonucleases with potential for delivery-constrained genome en...

Architecture of a DNA-guided Cas12a.

CRISPR-Cas systems have largely been restricted to RNA-guided nucleases. Here, we present the cryo-electron microscopy structure of Acidaminococcus sp. Cas12a bound to a pseudo-DNA (ΨDNA) guide and RNA target, revealing how Cas12a can accomplish DNA-guided RNA recognition. The ΨDNA hairpin bridges the recognition and n...

CRISPR RNA architecture steers Cas9 catalysis and fidelity via a guide repeat clasp motif

A previously unknown mechanism that steers Cas9 catalysis is uncovered and the potential to improve Cas9 fidelity by modulating guide repeat interactions is demonstrated.