TY - JOUR
T1 - Conserved motifs in the CRISPR leader sequence control spacer acquisition levels in Type I-D CRISPR-Cas systems
AU - Kieper, Sebastian N.
AU - Almendros, Cristóbal
AU - Brouns, Stan J.J.
PY - 2019
Y1 - 2019
N2 - Integrating short DNA fragments at the correct leader-repeat junction is key to successful CRISPR-Cas memory formation. The Cas1-2 proteins are responsible to carry out this process. However, the CRISPR adaptation process additionally requires a DNA element adjacent to the CRISPR array, called leader, to facilitate efficient localization of the correct integration site. In this work, we introduced the core CRISPR adaptation genes cas1 and cas2 from the Type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and assessed spacer integration efficiency. Truncation of the leader resulted in a significant reduction of spacer acquisition levels and revealed the importance of different conserved regions for CRISPR adaptation rates. We found three conserved sequence motifs in the leader of I-D CRISPR arrays that each affected spacer acquisition rates, including an integrase anchoring site. Our findings support the model in which the leader sequence is an integral part of type I-D adaptation in Synechocystis sp. acting as a localization signal for the adaptation complex to drive CRISPR adaptation at the first repeat of the CRISPR array.
AB - Integrating short DNA fragments at the correct leader-repeat junction is key to successful CRISPR-Cas memory formation. The Cas1-2 proteins are responsible to carry out this process. However, the CRISPR adaptation process additionally requires a DNA element adjacent to the CRISPR array, called leader, to facilitate efficient localization of the correct integration site. In this work, we introduced the core CRISPR adaptation genes cas1 and cas2 from the Type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and assessed spacer integration efficiency. Truncation of the leader resulted in a significant reduction of spacer acquisition levels and revealed the importance of different conserved regions for CRISPR adaptation rates. We found three conserved sequence motifs in the leader of I-D CRISPR arrays that each affected spacer acquisition rates, including an integrase anchoring site. Our findings support the model in which the leader sequence is an integral part of type I-D adaptation in Synechocystis sp. acting as a localization signal for the adaptation complex to drive CRISPR adaptation at the first repeat of the CRISPR array.
KW - CRISPR adaptation
KW - CRISPR leader
KW - spacer acquisition
KW - type I-D CRISPR-Cas system
UR - http://www.scopus.com/inward/record.url?scp=85069265187&partnerID=8YFLogxK
U2 - 10.1093/femsle/fnz129
DO - 10.1093/femsle/fnz129
M3 - Article
C2 - 31252430
SN - 0378-1097
VL - 366
JO - FEMS Microbiology Letters
JF - FEMS Microbiology Letters
IS - 11
M1 - fnz129
ER -