title: The eukaryotic way to defend and edit genomes by sRNA-targeted DNA deletion.
abstract: While there is currently burgeoning interest in the application of the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated genes) to genome editing, it is perhaps not widely appreciated that this is the second discovery of a small RNA (sRNA)-targeted DNA-deletion system. The first sRNA-targeted DNA-deletion system to be discovered, which we call IES/Ias (internal eliminated sequence/IES-associated genes) to contrast with CRISPR/Cas, is found in ciliates, and, like CRISPR/Cas, is thought to serve as a form of immune defense against invasive DNAs. The manner in which the ciliate IES/Ias system functions is distinct from that of the CRISPR/Cas system in archaea and bacteria, and arose independently through a synthesis of RNA interference-derived and DNA-specific molecular components. Despite the major differences between CRISPR/Cas and IES/Ias, both systems face similar conceptual challenges in targeting invasive DNAs. In this review, we focus on the discovery, effects, function, and evolutionary consequences of the IES/Ias system.
authors.affiliation: Institute of Cell Biology, University of Bern, Bern, Switzerland.
authors.forename: Estienne C
authors.initials: EC
authors.lastname: Swart
authors.forename: Mariusz
authors.initials: M
authors.lastname: Nowacki
mesh_terms: D001105:Archaea / Q000235:genetics; D001419:Bacteria / Q000235:genetics; D064112:Clustered Regularly Interspaced Short Palindromic Repeats / Q000235:genetics; D004247:DNA / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics*; D019143:Evolution, Molecular; D016678:Genome / Q000235:genetics*; D008957:Models, Genetic; D058727:RNA, Small Untranslated / Q000235:genetics*; D017384:Sequence Deletion
chemical_list: D058727:RNA, Small Untranslated; D004247:DNA
keywords: CRISPR/Cas; DNA excision; IES/Ias; genome editing; sRNA; sRNA-targeted DNA deletion