In a surprising finding, Landesman et al. (page 929) obtained results that diverge from previous analyses of junctional communication during Xenopus laevis embryogenesis. While a number of studies have reported that asymmetries arise in the patterns of gap junction communication during dorso-ventral patterning, this new work suggests a new model to explain these apparent asymmetries.
Xenopus embryos have been the principal model for studies on gap junctional intercellular communication in development. Earlier studies tracing the transfer of Lucifer yellow between cells led to models in which better gap junctional coupling between dorsal cells compared with ventral cells plays a role in dorso-ventral patterning. To analyze this process more thoroughly, the authors compared the transfer of Lucifer yellow and neurobiotin in embryos, coinjecting the junction-permeable tracer with a fluorescent dextran which cannot pass through gap junctions. Though their results in...
