A BETA(1)-INTEGRIN ASSOCIATED ALPHA-CHAIN IS DIFFERENTIALLY EXPRESSED DURING XENOPUS EMBRYOGENESIS

The antigen of mAb 2F10 was identified as a Xenopus beta(1)-integrin associated alpha-chain by the criteria (1) that it coprecipitates with anti beta(1)-antibody, (2) that it changes molecular mass upon reduction in a way that is characteristic for integrin alpha-chains and (3) that it is present on cell membranes. This alpha-chain, termed alpha(2F10), is found in small amounts in the pregastrula stages of Xenopus development and accumulates thereafter in the embryo. alpha(2F10) can be detected by immunofluorescence first at stage 17 of embryogenesis on the cell membranes of the sensorial layer of the ectoderm, the notochord and the endoderm. This characteristic pattern of distribution is maintained throughout the following embryonic stages. Timed explantation experiments indicate that all cells of the pregastrula have the potency to express alpha(2F10). This potency becomes successively restricted during gastrulation to yield the ultimate pattern of expression.