Table 4.

Features of the Type III CRISPR–Cas systems and effector complexes

Organism	Sub-type	Complex acronym	Repeat length, nt	Repeat sequence	Spacer length, nt	crRNA length, nt	Target	Cleavage position	Complex composition	Ref.
Staphylococcus epidermidis RP62Aa	III-A		36	5′-GTTCTCGTCCCCTTTTCTT CGGGGTGGGTATCGATCC-3′b	34–35	37 or 43	dsDNAc	nd	nd	[98, 105]
Pyrococcus furiosus	III-B	Pf-Cmr	30	5′-GTTCCAATAAGACTA CAAAAGAATTGAAAG-3′	36–42	39 or 45	ssRNA	14 nt from 3′ crRNA end	Cmr1, Cas10, Cmr3–6	[24, 106]
Sulfolobus solfataricus P2	III-B	Ss-Cmr	24–25	5′-GATAATCTCTTATAG AATTGAAAG-3′	36–44	45–50	ssRNA (including crRNA)	At UA dinucleotide	Cmr1, Cas10, Cmr3–7	[26]

^aThe effector complex has not been isolated or characterized

^bPalindromic sequences in the repeat are underlined

^cAccording to in vivo data [98]