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Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) RNAs in the Porphyromonas gingivalis CRISPR-Cas I-C System.

ABSTRACT: The CRISPR-Cas (clustered regularly interspaced short palindromic repeat-CRISPR-associated protein) system is unique to prokaryotes and provides the majority of bacteria and archaea with immunity against nucleic acids of foreign origin. CRISPR RNAs (crRNAs) are the key element of this system, since they are responsible for its selectivity and effectiveness. Typical crRNAs consist of a spacer sequence flanked with 5' and 3' handles originating from repeat sequences that are important for recognition of these small RNAs by the Cas machinery. In this investigation, we studied the type I-C CRISPR-Cas system in Porphyromonas gingivalis, a human pathogen associated with periodontitis, rheumatoid arthritis, cardiovascular disease, and aspiration pneumonia. We demonstrated the importance of the 5' handle for crRNA recognition by the effector complex and consequently activity, as well as secondary trimming of the 3' handle, which was not affected by modifications of the repeat sequence.IMPORTANCEPorphyromonas gingivalis, a clinically relevant Gram-negative, anaerobic bacterium, is one of the major etiologic agents of periodontitis and has been linked with the development of other clinical conditions, including rheumatoid arthritis, cardiovascular disease, and aspiration pneumonia. The presented results on the biogenesis and functions of crRNAs expand our understanding of CRISPR-Cas cellular defenses in P. gingivalis and of horizontal gene transfer in bacteria.

SUBMITTER: Burmistrz M

PROVIDER: S-EPMC5686588 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) RNAs in the Porphyromonas gingivalis CRISPR-Cas I-C System.

Burmistrz Michal M Rodriguez Martinez Jose Ignacio JI Krochmal Daniel D Staniec Dominika D Pyrc Krzysztof K

Journal of bacteriology 20171031 23

The CRISPR-Cas (clustered regularly interspaced short palindromic repeat-CRISPR-associated protein) system is unique to prokaryotes and provides the majority of bacteria and archaea with immunity against nucleic acids of foreign origin. CRISPR RNAs (crRNAs) are the key element of this system, since they are responsible for its selectivity and effectiveness. Typical crRNAs consist of a spacer sequence flanked with 5' and 3' handles originating from repeat sequences that are important for recognit ...[more]

PMID: 28893837

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Project description:BackgroundIn recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material are inactive or absent. One of these systems is CRISPR/Cas. However, little is known regarding the clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) system in K. pneumoniae. The adaptive immune system CRISPR/Cas has been shown to limit the entry of foreign genetic elements into bacterial organisms and in some bacteria it has been shown to be involved in regulation of virulence genes. Thus in this work we used bioinformatics tools to determine the presence or absence of CRISPR/Cas systems in available K. pneumoniae genomes.ResultsThe complete CRISPR/Cas system was identified in two out of the eight complete K. pneumoniae genomes sequences and in four out of the 44 available draft genomes sequences. The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different. As for the CRISPR sequences, the average lengths of the direct repeats and spacers were 29 and 33 bp, respectively. BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences. The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.ConclusionsThe CRISPR/Cas system is not widely distributed in K. pneumoniae genomes, those present most likely belong to type I-E with few differences from the arrangement of the cse3 gene and most of the spacers have not been are not described yet. Given that the CRISPR/Cas system is scarcely distributed among K. pneumoniae genomes it is not clear whether it is involved in either immunity against foreign genetic material or virulence. We consider that this study represents a first step to understand the role of CRISPR/Cas in K. pneumoniae.

Dataset Information

Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) RNAs in the Porphyromonas gingivalis CRISPR-Cas I-C System.

Publications

Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) RNAs in the Porphyromonas gingivalis CRISPR-Cas I-C System.

Similar Datasets

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