Frmpd1^em1Asw

CRISPR/Cas9 technology deleted the retinal alternate exon 1a (excision of basepairs -48 to +1033 relative to the retina transcriptional start signal) which contains the photoreceptor minimal promoter and neural retinal leucine zipper (NRL) and cone-rod homeobox (CRX) binding sites. The RPO1 sequence, the brain transcriptional start signal, and the translation start site are left unaltered such that only the rod photoreceptor-specific regulatory sequency of Frmpd1 is disrupted. In situ hybridization using probes specific for exon 1a shows no expression in rods with negligible transcripts in the retinal bipolar cells and using probes specific for exons 3-12 show a complete loss of mRNA in rods and very low level of expression in bipolar cells. Retina protein lysates show a drastic reduction, about 70%, in protein levels by immunoblotting. Frmpd1 protein expression is unaffected in the brain. (J:337797)