CELF1 and myotonic dystrophy type 1: However, in the cortex from DM1, we identified enrichment of CUGBP1 binding in the introns flanking BSJs of some upregulated SE-circRNAs (e.g., hsa-RC3H1_0001 and hsa-DCLK2_0001 had 96 and 62 CUGBP1 binding sites, respectively, within 250 bp downstream of the circularized exons).