Changes in the Nuclear Envelope of Amoeba during Mitosis

Abstract

IN Amoeba proteus, the interphase nucleus is surrounded by a complex envelope consisting of an outer double membrane and an inner honeycomb structure¹. Roth et al.² have found that during mitosis two morphological changes in the nuclear envelope complex can be detected with the electron microscope; first, the honeycomb structure disappears during the later stages of prophase (see also ref. 3) and, second, numerous gaps appear in the outer, membranous layer during metaphase (Fig. 1). Reconstruction of the membranous component of the envelope occurs shortly after anaphase², but the honeycomb structure does not completely reform until several hours after cytokinesis (my unpublished work).