Cell Growth & Differentiation, Vol 2, Issue 11 575-582, Copyright © 1991 by American Association of Cancer Research
Interaction of human immunodeficiency virus type I Rev protein with nuclear scaffold nucleoside triphosphatase activity
GA Clawson, YL Song, AM Schwartz, RR Shukla, SG Patel, L Connor, L Blankenship, C Hatem and A Kumar
Department of Pathology, Pennsylvania State University, Hershey 17033.
Human immunodeficiency virus type I encodes a regulatory protein, termed
Rev, which is associated with the appearance of unspliced and partially
spliced viral RNAs in the cytoplasm. Rev is believed to function via
interaction with a sequence element in the env region of the viral RNA,
termed the Rev-responsive element (RRE). In this study, we use a stably
transfected, Rev-producing mouse cell line to show that low, functional
levels of Rev are associated with the nuclear scaffold (NS).
Immunohistochemical studies localize Rev to the NS. Furthermore, immunoblot
analyses demonstrate the presence of Rev in NS preparations isolated from
Rev-producing cells and document binding of purified Rev protein to
isolated NS or to cloned lamin C in vitro. Results with an in vitro RNA
transport assay suggest that Rev is associated with a significant defect in
transport of RNAs which lack RRE, whereas transport of RRE-containing
transcripts proceeds efficiently. This Rev-induced transport defect appears
to be mediated via direct inhibition of NS nucleoside triphosphatase, an
enzyme thought to be involved in the nucleocytoplasmic transport process.
NS preparations isolated from Rev-producing cells show a significantly
lower nucleoside triphosphatase activity than those from control
preparations. Addition of Rev protein to isolated NS produces a significant
inhibition of NS nucleoside triphosphatase activity, which is specifically
reversed by addition of RRE transcripts. These data suggest that a major
aspect of Rev function may involve selective modulation of host cell
nucleocytoplasmic transport mechanisms via interaction with the NS.