NUDC expression during amphibian development

To identify gene products important for gastrulation in the amphibian Pleur odeles waltl, a screen for regional differences in new protein expression a t the early gastrula stage was performed. A 45 kDa protein whose synthesis was specific for progenitor endodermal cells was identified. Microsequencin g and cDNA cloning showed that P45 is highly homologous to rat NUDC, a prot ein suggested to play a role in nuclear migration. Although PNUDC can be de tected in all regions of the embryo, its de novo synthesis is tightly regul ated spatially and temporally throughout oogenesis and embryonic developmen t. New PNUDC synthesis in the progenitor endodermal cells depends on induct ion by the mesodermal cells in the gastrula, During development, PNUDC is l ocalized in the egg cortical cytoplasm, at the cleavage furrow during the f irst embryonic division, around the nuclei and cortical regions of bottle c ells in the gastrula, and at the basal region of polarized tissues in the d eveloping embryo. These results show for the first time the expression and compartmentalization of PNUDC at distinct stages during amphibian developme nt.