CRISPR-CAS9 targeting of RE1 sites. A, B, A sequence alignment of WT and snap25 RE1 site mutations (A) snap25asbu82 or (B) snap25bsbu83. Black represents the genomic sequence surrounding the RE1 site. Red represents RE1 site. C, E, qPCR analysis showing fold differences relative to the RE1 mutant transcript levels (defined as 1). Significance: p < 0.05 (Student's t test). D, F, RNA whole-mount in situ hybridization with (D) snap25a probe on a Snap25a RE1 sitesbu82/+ inx or (F) snap25b probe on a snap25b RE1 sitesbu83/+ inx. White bracket or white arrow indicates ectopic expression. OV, Otic vesicle; MB, midbrain. #Genotype (p < 0.05).