Feldherr C M, Lanford R E, Akin D
Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville 32610.
Proc Natl Acad Sci U S A. 1992 Nov 15;89(22):11002-5. doi: 10.1073/pnas.89.22.11002.
Transformation of cultured cells with simian virus 40 (SV40), or transfection with the early region of the SV40 genome, causes a significant increase in both the rate of signal-mediated nuclear transport and the functional size of the transport channels (located in the pore complexes). By microinjecting purified large tumor (T) antigen into the cytoplasm of murine BALB/c 3T3 cells, we have demonstrated that this protein alone can account for the increase in transport capacity. The T antigen-dependent changes can be partially inhibited by cycloheximide and require a functional nuclear localization sequence. Although necessary, the nuclear localization sequence by itself cannot produce the observed variations in nuclear permeability and presumably function in a "helper" capacity, in association with another, as yet unidentified domain.