Selective and hyperactive uptake of foreign DNA by adaptive immune systems of an archaeon via two distinct mechanisms

Erdmann, Susanne; Garrett, Roger A.

doi:10.1111/mmi.12062

Cited by 32 publications

(78 citation statements)

References 36 publications

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“…The spacers undergo Darwinian selection, and there may be strong selection for spacers which are especially effective [45].…”

Section: Crispr-cas and Lamarckian Evolutionmentioning

confidence: 99%

“…The repeat sequences of Archaea and Bacteria are also quite different; there is not much overlap between the sequences of families of CRISPR loci from these two domains. Additionally, while the repeats found in bacterial CRISPR loci allow for the formation of hairpin loops in their transcript, archaeal repeats generally do not create transcripts with this secondary structure [45]. Most likely, adaptations specific to each domain have occurred during the course of evolution.…”

Section: Origin Of Crispr-cas Systemsmentioning

confidence: 99%

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Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

Cooper

Overstreet

2014

Physics of Life Reviews

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Recent evidence supports that prokaryotes exhibit adaptive immunity in the form of CRISPR (Clustered Regularly Interspersed Short Palindromic Repeats) and Cas (CRISPR associated proteins). The CRISPR-Cas system confers resistance to exogenous genetic elements such as phages and plasmids by allowing for the recognition and silencing of these genetic elements. Moreover, CRISPR-Cas serves as a memory of past exposures. This suggests that the evolution of the immune system has counterparts among the prokaryotes, not exclusively among eukaryotes. Mathematical models have been proposed which simulate the evolutionary patterns of CRISPR, however large gaps in our understanding of CRISPR-Cas function and evolution still exist. The CRISPR-Cas system is analogous to small RNAs involved in resistance mechanisms throughout the tree of life, and a deeper understanding of the evolution of small RNA pathways is necessary before the relationship between these convergent systems is to be determined. Presented in this review are novel RNAi therapies based on CRISPR-Cas analogs and the potential for future therapies based on CRISPR-Cas system components.

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“…The spacers undergo Darwinian selection, and there may be strong selection for spacers which are especially effective [45].…”

Section: Crispr-cas and Lamarckian Evolutionmentioning

confidence: 99%

Section: Origin Of Crispr-cas Systemsmentioning

confidence: 99%

Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

Cooper

Overstreet

2014

Physics of Life Reviews

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“…New spacer integrations in CRISPR arrays generally take place in a unidirectional manner next to a sequence element just upstream of the repeatspacer array ("leader"), as first inferred in Yersinia pestis and later verified experimentally. 5,31,32 While rare exceptions to this rule have been reported, 33,34 directional integration allows to distinguish between recent and historical spacer acquisitions with implications for elucidating temporal dynamics of phage-host interactions and reconstructing approximate array evolution when compared across strains.…”

Section: Holding a Grudgementioning

confidence: 99%

Holding a grudge

2013

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T he CRISPR (clustered regularlyinterspaced short palindromic repeats)/Cas (CRISPR-associated) system of bacteria and archaea constitutes a mechanism of acquired adaptive immunity against phages, which is based on genome-encoded markers of previously infecting phage sequences ("spacers"). As a repository of phage sequences, these spacers make the system particularly suitable for elucidating phage-bacteria interactions in metagenomic studies. Recent metagenomic analyses of CRISPRs associated with the human microbiome intriguingly revealed conserved "memory spacers" shared by bacteria in multiple unrelated, geographically separated individuals. Here, we discuss possible avenues for explaining this phenomenon by integrating insights from CRISPR biology and phage-bacteria ecology, with a special focus on the human gut. We further explore the growing body of evidence for the role of CRISPR/Cas in regulating the interplay between bacteria and lysogenic phages, which may be intimately related to the presence of memory spacers and sheds new light on the multifaceted biological and ecological modes of action of CRISPR/Cas. IntroductionBacteriophages are known to play a crucial role in shaping the structure, diversity and evolution of microbial communities in various ecological niches. [1][2][3][4] The CRISPR (clustered regularly interspaced short palindromic repeats)/Cas Holding a grudgePersisting anti-phage CRISPR immunity in multiple human gut microbiomes (CRISPR-associated) system of bacteria and archaea constitutes a mechanism of acquired adaptive immunity against phages, which is based on genomeencoded markers of past infections. 5 The unique biology of this system has opened a window into the multifaceted interactions that take place in natural environments between microbial populations and their associated phages. At the same time, observation of these interactions raises intriguing questions about the underlying mechanistic activity of CRISPR/Cas. Here, we explore this reciprocity with a focus on the microbial community resident in the human gut.CRISPR loci are composed of a succession of short repeat sequences separated by unique "spacer" sequences, usually sized 24-50 bp. While the mechanism of action of the CRISPR/Cas system is not yet fully characterized and some specifics vary by subtype, it generally entails three processes: incorporation of fragments of phage or plasmid genomes as novel spacers in bacterial CRISPR arrays; transcription and processing of the array into small RNAs (crRNAs) and formation of a crRNA/Cas protein complex that recognizes foreign nucleic acids through sequence complementarity and interferes with phage replication. [6][7][8][9][10][11] Elucidation of the function of the CRISPR/Cas system has led to theoretical and experimental efforts at exploring the ecological impacts of CRISPR-mediated immunity, as well as the conditions under which its emergence would be favored. [12][13][14] However, this system provided an ©2012 Landes Bioscience. Do not distribute.

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“…51 Besides the large numbers of mobile genetic elements, genetic tools have been developed for several Sulfolobus species, 60,61 which allow to manipulate and functionally study the virus-host systems 62,63 as well as the CRISPR-based defense mechanism. 12,14,28 …”

Section: Crispr Transcription and Regulation In Sulfolobalesmentioning

confidence: 99%

“…10,28,29 The mechanism of recognition of the extra-chromosomal element as invader is still poorly understood. However, based on the enzymatic properties of the proteins involved in the recognition/integration of new spacers, [28][29][30][31][32][33] this process unlike the eukaryotic RNAi system, should not involve the presence of dsRNAs. [34][35][36] The CRISPR Cas system activity can be divided into three temporally and functionally distinct processes: adaptation, expression/processing and interference.…”

Section: Introductionmentioning

confidence: 99%

CRISPR-mediated defense mechanisms in the hyperthermophilic archaeal genusSulfolobus

Manica

Schleper²

2013

RNA Biology

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Selective and hyperactive uptake of foreign DNA by adaptive immune systems of an archaeon via two distinct mechanisms

Cited by 32 publications

References 36 publications

Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

Diversity, evolution, and therapeutic applications of small RNAs in prokaryotic and eukaryotic immune systems

Holding a grudge

CRISPR-mediated defense mechanisms in the hyperthermophilic archaeal genusSulfolobus

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