Functional interaction of nuclear transport-defective simian virus 40 large T antigen with chromatin and nuclear matrix

Abstract

mutant-transformed rodent cells and in Lys-128-mutant dlO-infected TC7 cells. Small but significant amounts of the mutant large T antigens were found in association with nuclear substructures, both in mutanttransformed and in mutant-infected cells. Experiments with TC7 cells made incompetent for cell division by "Co irradiation supported the assumption that Lys-128-mutant large T antigen did not associate with nuclear components during mitosis but most likely was transported into the nucleus because the Lys-128 mutation was leaky for nuclear transport. Low-level simian virus 40 DNA replication and production of infectious mutant virus progeny in TC7 cells indicated that the association of Lys-128-mutant large T antigen with nuclear substructures is functional.

Adenovirus precursor to terminal protein interacts with the nuclear matrix in vivo and in vitro

“…for studies of the function of the nuclear matrix. One widely studied DNA replication protein, the simian virus 40 large T antigen, has been shown to associate with nuclear matrix and, when bound, to continue elongation and termination of DNA replication (18,56). Although it is not clear whether the human papillomavirus 16 E7 protein is directly involved in DNA replication, it has been shown to interact with the matrix (32).…”

Dynamic continuity of nuclear and mitotic matrix proteins in the cell cycle

“…Interestingly, many of these Rb-binding proteins have been shown to be matrix-or mitotic apparatusassociated themselves, including lamins A and C [Mancini et al, 19941, p84 [Durfee et al, 19941, c-myc [Rustgi et al, 19911, hNUC [Chen et al, 19951 (hNUC is a human homologue of the yeast nucleoskeletal protein nuc2 [Hirano et al, 19881), protein phosphatase 1 [Durfee et al, 19931, and mitosin/CENP-F (see above) [Zhu et al, 1995bl. Inactivation of Rb by several viral oncoproteins (SV40 large T antigen, adenovirus E l a protein, or human papilloma protein E7) is well documented, and all target the nuclear matrix as well [Deppert and Von Der Weth, 1990;Chatterjee and Flint, 1986;Greenfield et al, 19911. One can envision these viral oncoproteins specifically targeting the matrix-bound Rb as a direct means to subvert cell cycle regulation.…”