Fine Structure of the Nuclear Envelope of Carcinoma Cells

Abstract

PALADE¹ was the first to observe with the electron microscope that the plasma membrane forms invagnations which occasionally plunge deeply into the cell body. He has shown that the lumen of the infoldings of the cell membrane communicates with the interior of the endoplasmic reticulum. Watson² showed that in certain cells the outer nuclear membrane is continuous with the membrane system of Palade's reticulum. Therefore, his ‘perinuclear space’ is part and parcel of the cavities of the endoplasmic reticulum. By demonstrating that the inner and outer nuclear membranes fuse at the edges of the nuclear pore, Watson² suggested that the nuclear envelope is simply a specialized form of endoplasmic reticulum.