Cadherin-23 and protocadherin-15 immunogold labelings in macaque photoreceptors. The C1EC25 and P1CD1-3 antibodies were used to detect cadherin-23 and protocadherin-15, respectively. (A, C, and E) Cadherin-23 (A) and protocadherin-15 (C and E) silver-enhanced immunogold particles are present along the apposing membranes of the macaque photoreceptor outer segment and calyceal processes. Gold particles are detected on either side, both at the edge of the outer segment (empty arrowheads) and at the calyceal processes (filled arrowheads). Quantitative analyses of the immunogold labeling for cadherin-23 (B) and protocadherin-15 (D) were performed on nine photoreceptors, subdivided into four regions (1, 2, 3, 4), as indicated in A and C. Gold particle distributions are expressed as the relative labeling index (RLI). In all the photoreceptors examined, numerous gold particles are observed along the calyceal processes and at the inner–outer segment interface. Rod photoreceptors display larger numbers of gold particles at the inner–outer segment interface for both cadherin-23 and protocadherin-15 (B and D), as illustrated in E. In cone photoreceptors, however, gold particles associate essentially with the calyceal processes (A–E). m, mitochondria. ***, P < 0.001 in χ2 test. Bars, 250 nm.
