[Morphogenesis of nuclear pockets in tumor cells in bovine leukosis]

In cases of lymphatic bovine leukemia, the nuclear pockets of the tumour cells in the lymph nodes contain part of cytoplasm and usually protrude above nucleus surface. A wall 60 to 90 nm thick forms the boundary between the nuclear pockets and cytoplasm. The wall consists of two complete nuclear membranes 25 nm thick with a 30-40 nm layer of heavily condensed heterochromatin in between. The nuclear membranes of the walls of the pockets have no nuclear pores. Extensive fusions, built from all the three layers, occur in the walls of the nuclear pockets. These pockets appear on nucleus surface when the plicae of the nuclear membrane are closed or when the apex of the plica merges with nucleus surface. Centriol is involved in the rise of the plicae of the nuclear membrane. The microtubuli inserted in the centriolar satellites on the one side merge with nucleus surface on the other side.