@article{8c9eedb2719342c3b4df307bd8728959,
title = "Adaptation induced by self-targeting in a type I-B CRISPR-Cas system",
abstract = "Haloferax volcanii is, to our knowledge, the only prokaryote known to tolerate CRISPR-Cas-mediated damage to its genome in the WT background; the resulting cleavage of the genome is repaired by homologous recombination restoring the WT version. In mutant Haloferax strains with enhanced self-targeting, cell fitness decreases and microhomology-mediated end joining becomes active, generating deletions in the targeted gene. Here we use self-targeting to investigate adaptation in H. volcanii CRISPR-Cas type I-B. We show that self-targeting and genome breakage events that are induced by self-targeting, such as those catalyzed by active transposases, can generate DNA fragments that are used by the CRISPR-Cas adaptation machinery for integration into the CRISPR loci. Low cellular concentrations of self-targeting crRNAs resulted in acquisition of large numbers of spacers originating from the entire genomic DNA. In contrast, high concentrations of self-targeting crRNAs resulted in lower acquisition that was mostly centered on the targeting site. Furthermore, we observed na{\"i}ve spacer acquisition at a low level in WT Haloferax cells and with higher efficiency upon overexpression of the Cas proteins Cas1, Cas2, and Cas4. Taken together, these findings indicate that na{\"i}ve adaptation is a regulated process in H. volcanii that operates at low basal levels and is induced by DNA breaks.",
keywords = "adaptation, archaea, CRISPR-Cas, crRNA, Haloferax volcanii, homologous recombination, naive adaptation, self-targeting, type I-B",
author = "Stachler, {Aris Edda} and Julia W{\"o}rtz and Alkhnbashi, {Omer S.} and Israela Turgeman-Grott and Rachel Smith and Thorsten Allers and Rolf Backofen and Uri Gophna and Anita Marchfelder",
note = "Publisher Copyright: {\textcopyright} 2020 Stachler et al. Published by The American Society for Biochemistry and Molecular Biology, Inc.",
year = "2020",
month = sep,
day = "25",
doi = "10.1074/jbc.RA120.014030",
language = "אנגלית",
volume = "295",
pages = "13502--13515",
journal = "The Journal of biological chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "39",
}