Fig 4.

Dissection of the roles of Cas proteins in crRNA biogenesis. (A) Northern blot of total RNA from the cas mutants and their parental strain (DF50) with the repeat probe. After exposure and stripping, a second hybridization was performed with the 7S RNA-specific probe serving as the internal control. (B) Northern blot with a repeat probe analyzing the products from the modified pWL502 vectors carrying a wild-type C2 array (pC2) or a variant array (pVC2) lacking the AT(C/T)GG(G/C)CATG leader motif (Fig. 2A). These plasmids were transformed into a CRISPR-free strain. Values to the left indicate RNA size markers, in nucleotides.