Which Factors Affect the Occurrence of Off-Target Effects Caused by the Use of CRISPR/Cas: A Systematic Review in Plants

作者：Dominik Modrzejewski, Frank Hartung, Heike Lehnert, Thorben Sprink, Christian Kohl, Jens Keilwagen, Ralf Wilhelm · 发表于：Frontiers in Plant Science · 年份：2020 · DOI：10.3389/fpls.2020.574959 · 被引用次数：144 · 研究领域：CRISPR and Genetic Engineering、Plant tissue culture and regeneration、Plant Virus Research Studies

CRISPR/Cas enables a targeted modification of DNA sequences. Despite their ease and efficient use, one limitation is the potential occurrence of associated off-target effects. This systematic review aims to answer the following research question: Which factors affect the occurrence of off-target effects caused by the use of CRISPR/Cas in plants? Literature published until March 2019 was considered for this review. Articles were screened for relevance based on pre-defined inclusion criteria. Relevant studies were subject to critical appraisal. All studies included in the systematic review were synthesized in a narrative report, but studies rated as high and medium/high validity were reported separately from studies rated as low and medium/low or unclear validity . In addition, we ran a binary logistic regression analysis to verify five factors that may affect the occurrence of off-target effects: (1) Number of mismatches (2) Position of mismatches (3) GC-content of the targeting sequence (4) Altered nuclease variants (5) Delivery methods. In total, 180 relevant articles were included in this review containing 468 studies therein. Seventy nine percentage of these studies were rated as having high or medium/high validity . Within these studies, 6,416 potential off-target sequences were assessed for the occurrence of off-target effects. Results clearly indicate that an increased number of mismatches between the on-target and potential off-target sequence steeply decreases the lik...