Institut de Génétique et Microbiologie

CRISPRs web server

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Université Paris Sud



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Data Summary

Genomes analysed CRISPRs found (*)
Archea 231 890(202)
Bacteria 6600 8732(3293)
Total 6831 9622(3495)

*number of convincing CRISPR structures (number of genomes with such CRISPR)

Database status:
Last update : 2017-01-02

Christine POURCEL

Welcome to CRISPRs web server. This site acts as a gateway to publicly accessible CRISPRs database and software. It enables the easy detection of CRISPRs in locally-produced data and consultation of CRISPRs present in the database. It also gives information on the presence of CRISPR-associated (cas) genes when they have been annotated as such.
This web site is the product of an original work by Ibtissem Grissa (PhD thesis Paris University) and is presently developed by Christine Drevet.

Please cite :
CRISPRFinder : a web tool to identify clustered regularly interspaced short palindromic repeats. Nucleic Acids Res. 2007 May 31;

The CRISPRdb database and tools to display CRISPRs and to generate dictionaries of spacers and repeats. BMC Bioinformatics. 2007 May 23;8(1):172 ;

CRISPRcompar : a website to compare clustered regularly interspaced short palindromic repeats. Nucleic Acid Res. 2008 Jul 1

What is a CRISPR?

CRISPR are direct repeats found in the DNA of many bacteria and archaea. The name is an acronym for Clustered Regularly Interspaced Short Palindromic Repeats.
These repeats range in size from 23 to 47 base pairs. They usually show some dyad symmetry but are not truly palindromic.
The repeats are separated by spacers of similar length. Spacers are usually unique in a genome. Some spacer sequences match sequences in phage genomes; it is proposed that these spacers derive from phage and subsequently help protect the cell from infection.
The CRISPR repeat array evolves rapidly.
More details.