Archaeal CRISPR-based immune systems: exchangeable functional modules

TY - JOUR

T1 - Archaeal CRISPR-based immune systems

T2 - exchangeable functional modules

AU - Garrett, Roger A

AU - Vestergaard, Gisle Alberg

AU - Shah, Shiraz Ali

N1 - Copyright © 2011 Elsevier Ltd. All rights reserved.

PY - 2011/11

Y1 - 2011/11

N2 - CRISPR (clustered regularly interspaced short palindromic repeats)-based immune systems are essentially modular with three primary functions: the excision and integration of new spacers, the processing of CRISPR transcripts to yield mature CRISPR RNAs (crRNAs), and the targeting and cleavage of foreign nucleic acid. The primary target appears to be the DNA of foreign genetic elements, but the CRISPR/Cmr system that is widespread amongst archaea also specifically targets and cleaves RNA in vitro. The archaeal CRISPR systems tend to be both diverse and complex. Here we examine evidence for exchange of functional modules between archaeal systems that is likely to contribute to their diversity, particularly of their nucleic acid targeting and cleavage functions. The molecular constraints that limit such exchange are considered. We also summarize mechanisms underlying the dynamic nature of CRISPR loci and the evidence for intergenomic exchange of CRISPR systems.

AB - CRISPR (clustered regularly interspaced short palindromic repeats)-based immune systems are essentially modular with three primary functions: the excision and integration of new spacers, the processing of CRISPR transcripts to yield mature CRISPR RNAs (crRNAs), and the targeting and cleavage of foreign nucleic acid. The primary target appears to be the DNA of foreign genetic elements, but the CRISPR/Cmr system that is widespread amongst archaea also specifically targets and cleaves RNA in vitro. The archaeal CRISPR systems tend to be both diverse and complex. Here we examine evidence for exchange of functional modules between archaeal systems that is likely to contribute to their diversity, particularly of their nucleic acid targeting and cleavage functions. The molecular constraints that limit such exchange are considered. We also summarize mechanisms underlying the dynamic nature of CRISPR loci and the evidence for intergenomic exchange of CRISPR systems.

KW - Archaea

KW - Bacteriophages

KW - Biological Evolution

KW - DNA, Archaeal

KW - Inverted Repeat Sequences

U2 - 10.1016/j.tim.2011.08.002

DO - 10.1016/j.tim.2011.08.002

M3 - Review

C2 - 21945420

SN - 0966-842X

VL - 19

SP - 549

EP - 556

JO - Trends in Microbiology

JF - Trends in Microbiology

IS - 11

ER -