Evolutionary classification of CRISPR–Cas systems: a burst of class 2 and derived variants
By Kira S. Makarova, Yuri I. Wolf, J. Iranzo, Sergey A. Shmakov, O. Alkhnbashi, Stan J. J. Brouns, E. Charpentier, David R. Cheng, Daniel H. Haft, Philippe Horvath and 16 more. Nature Reviews Microbiology, 2019
1,975 citations recorded by the source corpus.
The number and diversity of known CRISPR–Cas systems have substantially increased in recent years. Here, we provide an updated evolutionary classification of CRISPR–Cas systems and cas genes, with an emphasis on the major developments that have occurred since the publication of the latest classification, in 2015. The new classification includes 2 classes, 6 types and 33 subtypes, compared with 5 types and 16 subtypes in 2015. A key development is the ongoing discovery of multiple, novel class 2 CRISPR–Cas systems, which now include 3 types and 17 subtypes. A second major novelty is the discovery of numerous derived CRISPR–Cas variants, often associated with mobile genetic elements that lack the nucleases required for interference. Some of these variants are involved in RNA-guided transposition, whereas others are predicted to perform functions distinct from adaptive immunity that remain to be characterized experimentally. The third highlight is the discovery of numerous families of ancillary CRISPR-linked genes, often implicated in signal transduction. Together, these findings substantially clarify the functional diversity and evolutionary history of CRISPR–Cas. The number and diversity of known CRISPR–Cas systems have substantially increased in recent years. In this Review, Koonin and colleagues provide an updated evolutionary classification of CRISPR–Cas systems and cas genes, with an emphasis on major developments, and outline a complete scenario for the origins and evolution of CRISPR–Cas systems.
Subfields: Genetics, Molecular Biology
View Paper: https://www.semanticscholar.org/paper/c9d6a6e8362eab51d60032e7e615459928b034e6
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Citations in the corpus
- Type III CRISPR-Cas Systems: Deciphering the Most Complex Prokaryotic Immune System (2021, background): “10 2021 polymerase and a CARF HEPN effector protein that could produce nucleotide based secondary messengers (likely, cOAs) in response to stress/environmental signals, followed by the activation of the RNase activity of the CARF HEPN protein [4].”
- Rethinking Protein Drug Design with Highly Accurate Structure Prediction of Anti-CRISPR Proteins (2021, background): “Since the successful application of CRISPR-Cas systems as genome-editing tools [17,18], there has been a burst in the discovery of diverse CRISPR-Cas systems [19], followed by the discovery of Acr proteins that neutralize the activity of this prokaryotic adaptive immune system [20] (Figure 1b).”