Journal Article

Programmed DNA destruction by miniature CRISPR-Cas14 enzymes

Harrington, Lucas B., Kyrpides, Nikos C., Chen, Janice S., Witte, Isaac P., Banfield, Jillian F., Cofsky, Joshua C., Burstein, David, Paez-Espino, David, Ma, Enbo, Doudna, Jennifer A.

2018

Overview

CRISPR-Cas9 systems have been causing a revolution in biology. Harrington et al. describe the discovery and technological implementation of an additional type of CRISPR system based on an extracompact effector protein, Cas14. Metagenomics data, particularly from uncultivated samples, uncovered the CRISPR-Cas14 systems containing all the components necessary for adaptive immunity in prokaryotes. At half the size of class 2 CRISPR effectors, Cas14 appears to target single-stranded DNA without class 2 sequence restrictions. By leveraging this activity, a fast and high-fidelity nucleic acid detection system enabled detection of single-nucleotide polymorphisms. Science , this issue p. 839 Identification, characterization, and technological implementation of additional archaea-derived CRISPR-Cas14 systems are described. CRISPR-Cas systems provide microbes with adaptive immunity to infectious nucleic acids and are widely employed as genome editing tools. These tools use RNA-guided Cas proteins whose large size (950 to 1400 amino acids) has been considered essential to their specific DNA- or RNA-targeting activities. Here we present a set of CRISPR-Cas systems from uncultivated archaea that contain Cas14, a family of exceptionally compact RNA-guided nucleases (400 to 700 amino acids). Despite their small size, Cas14 proteins are capable of targeted single-stranded DNA (ssDNA) cleavage without restrictive sequence requirements. Moreover, target recognition by Cas14 triggers nonspecific cutting of ssDNA molecules, an activity that enables high-fidelity single-nucleotide polymorphism genotyping (Cas14-DETECTR). Metagenomic data show that multiple CRISPR-Cas14 systems evolved independently and suggest a potential evolutionary origin of single-effector CRISPR-based adaptive immunity.

• Publisher: The American Association for the Advancement of Science,AAAS
• Subject: Adaptive immunity / Adaptive systems / Amino acids / Archaea / Archaeal Proteins - chemistry / Archaeal Proteins - classification / Archaeal Proteins - genetics / BASIC BIOLOGICAL SCIENCES / CRISPR / CRISPR-Associated Proteins - chemistry / CRISPR-Associated Proteins - classification / CRISPR-Associated Proteins - genetics / Datasets as Topic / Deoxyribonucleic acid / DNA / DNA Cleavage / DNA, Single-Stranded - chemistry / Endodeoxyribonucleases - chemistry / Endodeoxyribonucleases - classification / Endodeoxyribonucleases - genetics / Evolution, Molecular / Fidelity / Genome editing / Genomes / Genotyping / Immunity / Metagenomics / Nuclease / Nucleic acids / Nucleotide sequence / Phylogeny / Polymorphism / Prokaryotes / Proteins / Ribonucleic acid / RNA / Single-nucleotide polymorphism / Single-stranded DNA / Target recognition