Subcellular localization of sperm-associated antigen (Spag)5 in retina cryosections of adult (postnatal day (P)20) rats. (A-C) Co-immunostaining using(A) anti-SPAG5 (green) and (B) anti-pan-centrin (red, a marker for the connecting cilium, basal body and centrioles) antibodies. (C) Colocalization (C; yellow) was detected at the (Ci) basal body (BB) and (Cii) in one of the two centrioles of the inner nuclear layer (INL). (A,C) Centriole staining is also visible in the ganglion cell layer (GCL). In addition, weaker Spag5 labeling was detected at the outer limiting membrane (OLM; filled arrowhead), the outer plexiform layer (OPL), at the distal part of the connecting cilium (CC) and at the accessory centriole. (A-Ci-ii).High-magnification fluorescence microscopy of the BB/CC region and the INL.