RNA in defense: CRISPRs protect prokaryotes against mobile genetic elements
Related Experiment Video
Updated: Jun 3, 2026

Selection-dependent and Independent Generation of CRISPR/Cas9-mediated Gene Knockouts in Mammalian Cells
Published on: June 16, 2017
Matthijs M Jore1, Stan J J Brouns, John van der Oost
1Laboratory of Microbiology, Wageningen University, Netherlands.
Abstract:
The CRISPR/Cas system in prokaryotes provides resistance against invading viruses and plasmids. Three distinct stages in the mechanism can be recognized. Initially, fragments of invader DNA are integrated as new spacers into the repetitive CRISPR locus. Subsequently, the CRISPR is transcribed and the transcript is cleaved by a Cas protein within the repeats, generating short RNAs (crRNAs) that contain the spacer sequence. Finally, crRNAs guide the Cas protein machinery to a complementary invader target, either DNA or RNA, resulting in inhibition of virus or plasmid proliferation. In this article, we discuss our current understanding of this fascinating adaptive and heritable defense system, and describe functional similarities and differences with RNAi in eukaryotes.
Related Concept Videos
The Antiviral System of Bacteria and Archaea: CRISPR
CRISPR and crRNAs
The CRISPR-Cas system stores a copy of foreign DNA in the host genome and uses it to identify the foreign DNA upon reinfection. CRISPR-Cas has three different...
CRISPR
CRISPR
CRISPR/Cas9 Genome Editing
Types of RNA
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...

