Characteristic tetraspanin expression patterns mark various tissues during Xenopus early development.

Tetraspanins (Tspans) are a four-pass transmembrane domain cell surface protein family. Tspans have been found on the plasma membrane and exosomes of various organelles. Reports on the function of tetraspanins during the early development of Xenopus have mainly focused on the expression of uroplakins in gametes. Although the roles of extracellular vesicles (EVs) including exosomes have been actively analyzed in cancer research, the contribution of EVs to early development is not well understood. This is because the diffusible property of EVs is not compatible with a very strict developmental process. In this study, we analyzed members of the tetraspanins in early development of Xenopus. The expression pattern was prominent in specific organs such as the notochord, eye, cranial neural crest cells (CNCs), trunk neural crest cells, placodes, and somites. We tested overexpressions of several different combination of Tspans expressing in CNC in vitro, and in vivo. Changing the partner changed the distribution of fluorescent-labeled Tspans. Therefore, it suggested that multiple Tspan expressions in particular tissue might produce heterogeneity of intercellular communication, which has not yet been recognized.