CRISPR Plasmids: Zebrafish

Cut

Fully functional CRISPR/Cas enzymes will introduce a double-strand break (DSB) at a specific location based on a gRNA-defined target sequence. DSBs are preferentially repaired in the cell by non-homologous end joining (NHEJ), a mechanism which frequently causes insertions or deletions (indels) in the DNA. Indels often lead to frameshifts, creating loss of function alleles.

To introduce specific genomic changes, researchers use ssDNA or dsDNA repair templates with homology to the DNA flanking the DSB and a specific edit close to the gRNA PAM site. When a repair template is present, the cell may repair a DSB using homology-directed repair (HDR) instead of NHEJ. In most experimental systems, HDR occurs at a much lower efficiency than NHEJ.

Empty gRNA Expression Vectors

Select a gRNA expression plasmid based on factors such as selectable marker or cloning method. When using CRISPR, you will need to express both a Cas protein and a target-specific gRNA in the same cell at the same time. Single plasmids containing both the gRNA and Cas protein act as all-in-one vectors, but their function is often limited to a single category (cut, nick, etc.) On the other hand, gRNA plasmids that do not co-express a Cas protein can be paired with a wide variety of Cas-containing plasmids.