METAMORPHIC CHANGE IN EP37 EXPRESSION - MEMBERS OF THE BETA-GAMMA-CRYSTALLIN SUPERFAMILY IN NEWT

EP37 is an epidermis-specific protein found in the developing embryo o f the Japanese newt, Cynops pyrrhogaster. Our previous study predicted the presence of genes homologous to EP37, which show temporary shared expression at the turn of metamorphosis. In this study, we isolated a nd characterized three cDNAs encoding novel EP37 homologues; two from the skin of an adult newt and the other from swimming larva. Conceptua l translation of the open reading frames of these cDNAs predicted prot eins carrying beta gamma-crystallin motifs and putative calcium-bindin g sites, both of which are features shared by the originally identifie d EP37 (EP37L1), as well as a spore coat protein of Myxococcus xanthus , protein S. Immunoblot analyses and immunohistochemical studies indic ated that two of the EP37 proteins, EP37L1 and EP37L2, are exclusively expressed in the epidermis (skein cells) including the figures of Ebe rth at premetamorphic stages. During and after metamorphosis, the expr ession of EP37 proteins was mainly observed in cutaneous glands, and a molecular transition to the adult types of EP37, EP37A1 and EP37A2, o ccurred. These observations suggest that EP37 proteins play an importa nt role in construction of integumental tissues and adaptation to the aquatic or amphibious environment.