EXPRESSION OF CYCLOPHILIN DURING THE EMBRYONIC-DEVELOPMENT OF THE SEA-URCHIN

The spatial and temporal expression pattern of cyclophilin (Cyp) was e xamined during the embryonic development of the sea urchins Anthocidar is crassispina and Hemicentrotus pulcherrimus using Western blot analy sis and indirect immunofluorescence microscopy. In this study, affinit y-purified anti-human Cyp A antibody was used as the primary antibody. Western blot analysis revealed that a single 17.5 kDa immunoreactive band of Cyp was present in unfertilized eggs, in embryos during severa l stages of development, and in ovaries and testes of adult sea urchin s. Cyp was also recognized in unfertilized eggs and embryonic sea urch in cells by indirect immunofluorescence microscopy, but its concentrat ions within the embryonic tissues varied significantly during embryoge nesis. Expression of Cyp during the cleavage stage was thought to be a ttributable to maternal Cyp products, with zygotic expression appearin g after gastrulation. Cyp expression appears to increase depending on the Cyp concentration in the vegetal and apical plates and primary mes enchyme cells in mesenchyme blastulae, and in the oral ectodermal ridg e, gut and skeletogenetic mesenchyme cells in pluteus larvae. These re sults suggest that widespread embryonic distribution and an increased Cyp content occur during the gastrulation in sea urchin development.