THE PROLIFERATING CELL MARKER MONOCLONAL-ANTIBODY KI-67 RECOGNIZES SPECIFIC ANTIGENS ASSOCIATED WITH THE NUCLEAR-ENVELOPE OF THE EARLY DROSOPHILA EMBRYO

Immunofluorescence and immunoelectron microscopy indicated that the an tibody raised against the nuclear antigen Ki-67 of mammalian cells rec ognized antigenic determinants of early Drosophila embryos, localized on the outside of the nuclear envelope. Hence, the nuclear envelope of Drosophila appears to share a similar epitope with the chromosome sca ffold of mitotic mammalian cells. With the progression of mitosis the antigen persisted around the mitotic spindle region and was also found in the pole regions at metaphase and anaphase. The antibody also stai ned the equatorial regions of the spindles from anaphase to late telop hase. The antibody may therefore be used as a biochemical marker of th e nuclear envelope for studying nuclear membrane biogenesis and behavi or during the mitotic divisions of the Drosophila embryo.