CRISPR Plasmids: CRISPR Transposases (CASTs)

CRISPR-associated transposases (CASTs) combine the large-scale capacity of transposases (Tns) with the precise DNA-targeting of CRISPR-Cas systems, allowing for the integration of large fragments of DNA at specific locations. The Cas effector lacks nuclease activity, instead recruiting the transposase (comprised of multiple components) to target locations in the genome defined by a guide RNA. The transposase can then integrate donor DNA. Editing by CASTs is not considered "scarless", as the transposon homology sequences are integrated along with the donor DNA.

The two main classes of CASTs are type I and type V-K. Type I systems use a type I Cas effector, composed of several separate Cas enzymes that form a complex called Cascade (CRISPR-associated complex for antiviral defense), and four transposase components (TnsA, TnsB, TnsC, and TniQ). Type I CASTs can result in bidirectional insertions and may not be suitable for applications where orientation matters. Type V-K systems use a type V-K Cas effector, Cas12k, and three transposase components (TnsB, TnsC, and TniQ). Unlike type I, type V-K CASTs appear to exhibit almost unidirectional insertions, but are more prone to off-target insertions.

CASTs are most often used in bacteria genome editing, though some mammalian systems have been developed.

Figure 1: Overview of the basic CAST mechanism. Created with BioRender.com.

Browse, sort, or search the tables below for CRISPR Transposase plasmids.
Plasmids are available for expression in mammalian systems and bacteria.

Mammalian

Bacteria

Last reviewed on: January 30, 2025