CRISPR Plasmids: C. elegans

The following CRISPR plasmids have been designed for use in C. elegans.

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.

Activate

Catalytically dead dCas9 fused to a transcriptional activator peptide can increase transcription of a specific gene. Design your gRNA sequence to direct the dCas9-activator to promoter or regulatory regions of your gene of interest. If the plasmid that you choose does not also express a gRNA, you will need to use a separate gRNA expression plasmid to target the dCas9-activator to your specific locus.

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.

	gRNA Plasmid	Promoter	Cloning Enzyme(s)	Delivery	Resistance	Co-expressed Cas9	Depositing lab
Cas9 species = S. pyogenes (PAM = NGG)
	pMB70	cU6	BsaI	Transfection		none, need Cas9 plasmid	Boxem
	pMB60	T7	BsaI	In vitro transcription		none, need Cas9 plasmid	Boxem
	PU6::klp-12_sgRNA	cU6	PCR (see paper)	Transfection		none, need Cas9 plasmid	Calarco
	pDD162 (Peft-3::Cas9 + Empty sgRNA)	R07E5.16 U6				yes, cut	Goldstein
	DR274	T7	BsaI	In vitro transcription		none, need Cas9 plasmid	Joung
	SP6-sgRNA-scaffold	SP6	AflII	In vitro transcription		none, need Cas9 plasmid	Sternberg
	L4440_BioBrick-sgRNA	T7	BbsI, BsaI	Ingestion by C. elegans		none, need Cas9 plasmid	Ristow