Target Motifs Affecting Natural Immunity by a Constitutive CRISPR-Cas System in Escherichia coli
نویسندگان
چکیده
Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR associated (cas) genes conform the CRISPR-Cas systems of various bacteria and archaea and produce degradation of invading nucleic acids containing sequences (protospacers) that are complementary to repeat intervening spacers. It has been demonstrated that the base sequence identity of a protospacer with the cognate spacer and the presence of a protospacer adjacent motif (PAM) influence CRISPR-mediated interference efficiency. By using an original transformation assay with plasmids targeted by a resident spacer here we show that natural CRISPR-mediated immunity against invading DNA occurs in wild type Escherichia coli. Unexpectedly, the strongest activity is observed with protospacer adjoining nucleotides (interference motifs) that differ from the PAM both in sequence and location. Hence, our results document for the first time native CRISPR activity in E. coli and demonstrate that positions next to the PAM in invading DNA influence their recognition and degradation by these prokaryotic immune systems.
منابع مشابه
The Cas6e ribonuclease is not required for interference and adaptation by the E. coli type I-E CRISPR-Cas system
CRISPR-Cas are small RNA-based adaptive prokaryotic immunity systems protecting cells from foreign DNA or RNA. Type I CRISPR-Cas systems are composed of a multiprotein complex (Cascade) that, when bound to CRISPR RNA (crRNA), can recognize double-stranded DNA targets and recruit the Cas3 nuclease to destroy target-containing DNA. In the Escherichia coli type I-E CRISPR-Cas system, crRNAs are ge...
متن کاملThe Streptococcus thermophilus CRISPR/Cas system provides immunity in Escherichia coli
The CRISPR/Cas adaptive immune system provides resistance against phages and plasmids in Archaea and Bacteria. CRISPR loci integrate short DNA sequences from invading genetic elements that provide small RNA-mediated interference in subsequent exposure to matching nucleic acids. In Streptococcus thermophilus, it was previously shown that the CRISPR1/Cas system can provide adaptive immunity again...
متن کاملThe action of Escherichia coli CRISPR–Cas system on lytic bacteriophages with different lifestyles and development strategies
CRISPR-Cas systems provide prokaryotes with adaptive defense against bacteriophage infections. Given an enormous variety of strategies used by phages to overcome their hosts, one can expect that the efficiency of protective action of CRISPR-Cas systems against different viruses should vary. Here, we created a collection of Escherichia coli strains with type I-E CRISPR-Cas system targeting vario...
متن کاملCRISPR-Cas: the effective immune systems in the prokaryotes
Approximately all sequenced archaeal and half of eubacterial genomes have some sort of adaptive immune system, which enables them to target and cleave invading foreign genetic elements by an RNAi-like pathway. CRISPR–Cas (clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins) systems consist of the CRISPR loci with multiple copies of a short repeat sequence separa...
متن کاملInterference by clustered regularly interspaced short palindromic repeat (CRISPR) RNA is governed by a seed sequence.
Prokaryotic clustered regularly interspaced short palindromic repeat (CRISPR)/Cas (CRISPR-associated sequences) systems provide adaptive immunity against viruses when a spacer sequence of small CRISPR RNA (crRNA) matches a protospacer sequence in the viral genome. Viruses that escape CRISPR/Cas resistance carry point mutations in protospacers, though not all protospacer mutations lead to escape...
متن کامل