Norrin binding activity of NCM460 and RKO cells after partitioned co-culture. Norrin binding was downregulated by Wnt2, but not Wnt3a in normal colonic mucosa-derived NCM460 cells. Each experiment was repeated three times with six (panel A) or five (panel B) replicates for each data point. A. Comparison of norrin binding in NCM460 (left) and RKO (right) after exposure to sham-transfected cells and Wnt2-producing cells in partitioned co-culture (Pcc). The decrease in norrin binding in NCM460 is highly statistically significant (p < 0.01). B. Comparison of norrin binding in NCM460 (left) and RKO (right) after exposure to control (L-cell) and Wnt3a conditioned medium (CM). No statistically significant difference was seen.