Structural basis for target site selection in RNA-guided DNA transposition systems
Jung-Un Park, Amy Wei-Lun Tsai, Eshan Mehrotra, Michael T. Petassi, Shan-Chi Hsieh, Ailong Ke, Joseph E. Peters, Elizabeth H. Kellogg
Abstract
Target site selection in CAST systems Exciting genomic engineering possibilities exist for natural integration systems called transposons, which have co-opted CRISPR/Cas systems. An unexplained feature of these systems involves how they direct insertions in a single orientation at a precise distance from the programmed target sequence. Park et al . show that orientation information is communicated to the transposase, TnsB, using the unidirectional growth of a helical filament made up of an AAA+ protein, TnsC. ATP hydrolysis trims the filament to a minimal unit that is marked by TniQ and defined by the Cas12k protein to provide spacing information. This finding may help future engineering of these systems for therapeutic applications. —DJ