SIMILARITY OF AN OVIDUCT-SPECIFIC GLYCOPROTEIN BETWEEN DIFFERENT SPECIES

The oviduct provides the best environment in which a zygote can grow a nd it can also support the development of embryos from a different spe cies. However, there is no clear explanation of its embryotrophic prop erties at present. In several species, oviduct epithelial cells synthe size and secrete glycosylated proteins that become associated with dev eloping embryos. Although these macromolecules may have a functional r ole at the time of fertilization and early embryonic development, the nature of such a role remains to be elucidated. The aim of this work w as to perform a comparative analysis of oviduct-specific glycoproteins in search of molecules common to different species since their phylog enetic conservation would imply biological significance. In previous s tudies, sheep oviduct-specific proteins were characterized and a monoc lonal antibody (AFRC MAC 264) specific for the sheep oviduct protein 9 2 (sOP 92) was produced; hence, sheep was taken as the reference speci es. The degree of similarity between sheep glycoproteins and those of the cow, goat, pig, rabbit and mouse was determined on the basis of: t he presence of carbohydrate sidechains, cross-reactivity with AFRC MAC 264, correspondence of molecular weight between crossreacting molecul es, and similarity of immunohistochemical localization. On this basis, proteins similar to sOP 92 were present in cow and goat oviduct. A mo re limited similarity was also observed in pigs. This indicates a cert ain degree of phylogenetic conservation and suggests that these molecu les may play an important physiological role; however, their function remains to be determined.