Crb1^em4Jnk

CRISPR/Cas9 technology generated a 13,783 bp deletion from chr1: 139,257,194-139,243,411, deleting the entire first exon of the B isoform (Crb1-B) and the promoter region in addition to exon 6 and part of exon 7 of the A isoform (Crb1-A). This deletion eliminates the exon 7 splice acceptor and is predicted to exclude exon 7 altogether. Splicing from exons 5 to 8 (as in the A isoform) and 4 to 8 (as in the A2 isoform) would result in frameshifts. The C isoform-specific retained intron after exon 6 is also entirely deleted. Thus this deletion disrupts all isoforms and generates a null allele. (J:293375)