Drosophila gp210, an invertebrate nuclear pore complex glycoprotein

Monoclonal antibodies were used to localize the putative Drosophila homolog of mammalian nuclear pore complex glycoprotein, gp210, to Drosophila nuclear pore complexes. Both immunofluorescence and immunoelectron microscopy mere performed. To the best of our knowledge, this establishes Drosophila gp210 as the first invertebrate gp210 homolog. Results of developmental studies demonstrated that like nuclear lamin and DNA topoisomerase II, gp210 is found abundantly in nonnuclear form early in embryogenesis where it presumably fuels the rapid assembly of new nuclei. Unlike these other two proteins, gp210 levels are maximal early after which they decrease significantly; in addition, nonnuclear gp210 found in early Drosophila embryos is apparently associated with membrane vesicles. These results have implications for understanding the regulation of higher eukaryotic nuclear pore complex behavior through development as well as for determining gp210 function genetically.