Xenopus laevis L-14 lectin is expressed in a typical pattern in the adult, but is absent from embryonic tissues

Soluble, dimeric, lactose-binding lectins with subunit M(r) of approximately 14-16 x 10(3), here called L-14s, are expressed in multiple tissues in all vertebrates that have been examined. L-14s have particular affinity for polylactosamine chains on laminin, co-localize with laminin in some basement membranes, and influence adhesion to laminin and proliferation for some cultured cells. In previous studies of mammals and chickens, L-14s have been found at high levels in a variety of adult tissues, such as muscle and peripheral nerve, but at much higher levels in many embryonic tissues, suggesting a special role in development. To further explore possible roles of L-14 in embryogenesis, we have studied the expression of L-14 in embryonic and adult Xenopus laevis tissues. Xenopus skin, we find that Xenopus L-14 is expressed in the same general distribution as its mammalian homologues. However, we could detect no expression of L-14 in Xenopus embryos using either a sensitive immunoassay for the protein or a sensitive RNase protection assay for its mRNA. Furthermore, use of affinity chromatography to identify other lactose-binding lectins in embryonic tissue revealed only scarce proteins with higher subunit molecular weights. These results suggest that in X.laevis L-14 functions in adult tissues and is not involved in embryogenesis.