Immunohistochemical cross-reactivity and electrophoretic comigration between calbindin D-27 kDa and visinin

Calbindin D-27 kDa (previously named vitamin D-CaBP or cholecalcin) and visinin present similitude both for their purification procedure and histochemical localization. We systematically compared by histochemistry calbindin and visinin immunoreactive structures in chick and pigeon retina, in rat cerebellum and kidney and in pigeon cerebellum. The calbindin and visinin immunoreactive structures were identical except in the retina. Preabsorption of anti-visinin with purified chick or rat calbindin suppresses the labelling in every organ studied except in the photoreceptor layer of pigeon and chick retina. Such a persistence of labelling was explained by Western blotting analysis of chick-retina soluble proteins showing a pattern of 7 different proteins recognized by anti-visinin even though only one protein was recognized in rat kidney and cerebellum. Anti-visinin is thus a polyclonal antibody reacting with more than one antigen of the chick retina, one of those antigens being calbindin. Calbindin is the single antigen recognized by anti-visinin in the other tested organs. In conclusion, we present evidence that visinin is a calbindin.