REMODELING OF NUCLEAR ARCHITECTURE DURING THE CELL-CYCLE IN DROSOPHILA EMBRYOS

Little is known about what determines the nuclear matrix or how its re organization is regulated during mitosis. In this study we report on a monoclonal antibody, mAb2A, which identifies a novel nuclear structur e in Drosophila embryos which forms a diffuse meshwork at interphase b ut which undergoes a striking reorganization into a spindle-like struc ture during pro- and metaphase. Double labelings with alpha-tubulin an d mAb2A antibodies demonstrate that the microtubules of the mitotic ap paratus co-localize with this mAb2A labeled structure during metaphase , suggesting it may serve a role in microtubule spindle assembly and/o r function during nuclear division. That the mAb2A-labeled nuclear str ucture is essential for cell division and/or maintenance of nuclear in tegrity was directly demonstrated by microinjection of mAb2A into earl y syncytial embryos which resulted in a disintegration of nuclear morp hology and perturbation of mitosis. (C) 1996 Wiley-Liss, Inc.