Sequences spanning the leader-repeat junction mediate CRISPR adaptation to phage in Streptococcus thermophilus
| Autor: | Rebecca M. Terns, Yunzhou Wei, Megan T. Chesne, Michael P. Terns |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Genetics
Trans-activating crRNA 0303 health sciences CRISPR interference Streptococcus Phages Base Sequence 030306 microbiology Molecular Sequence Data RNA Locus (genetics) Biology Adaptation Physiological 03 medical and health sciences Plasmid Sequence Homology Nucleic Acid DNA Viral CRISPR Loci Direct repeat CRISPR Streptococcus thermophilus Clustered Regularly Interspaced Short Palindromic Repeats Molecular Biology 030304 developmental biology |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 |
| Popis: | CRISPR-Cas systems are RNA-based immune systems that protect prokaryotes from invaders such as phages and plasmids. In adaptation, the initial phase of the immune response, short foreign DNA fragments are captured and integrated into host CRISPR loci to provide heritable defense against encountered foreign nucleic acids. Each CRISPR contains a ∼100–500 bp leader element that typically includes a transcription promoter, followed by an array of captured ∼35 bp sequences (spacers) sandwiched between copies of an identical ∼35 bp direct repeat sequence. New spacers are added immediately downstream of the leader. Here, we have analyzed adaptation to phage infection in Streptococcus thermophilus at the CRISPR1 locus to identify cis-acting elements essential for the process. We show that the leader and a single repeat of the CRISPR locus are sufficient for adaptation in this system. Moreover, we identified a leader sequence element capable of stimulating adaptation at a dormant repeat. We found that sequences within 10 bp of the site of integration, in both the leader and repeat of the CRISPR, are required for the process. Our results indicate that information at the CRISPR leader-repeat junction is critical for adaptation in this Type II-A system and likely other CRISPR-Cas systems. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|