|
|
|
|
|
|
|
||
© The Rockefeller University Press,
0021-9525/2001//895 $5.00
The Journal of Cell Biology, Volume 152, Number 5,
, 2001 895-910
Original Article |
Cofactor Requirements for Nuclear Export of Rev Response Element (Rre)–And Constitutive Transport Element (Cte)–Containing Retroviral Rnas
: An Unexpected Role for Actin
b Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037
c Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, D-91054 Erlangen, Germany
d Max-Planck-Institute for Biochemistry, D-82152 Martinsried, Germany
e Cell Biology, Zoological Institute, Technical University of Braunschweig, D-38092 Braunschweig, Germany
Department of Cell and Developmental Biology, Biocenter of the University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.49-931-888-425249-931-888-4273
mcd{at}biozentrum.uni-wuerzburg.de
Nuclear export of proteins containing leucine-rich nuclear export signals (NESs) is mediated by the export receptor CRM1/exportin1. However, additional protein factors interacting with leucine-rich NESs have been described. Here, we investigate human immunodeficiency virus type 1 (HIV-1) Rev-mediated nuclear export and Mason-Pfizer monkey virus (MPMV) constitutive transport element (CTE)–mediated nuclear export in microinjected Xenopus laevis oocytes. We show that eukaryotic initiation factor 5A (eIF-5A) is essential for Rev and Rev-mediated viral RNA export, but not for nuclear export of CTE RNA. In vitro binding studies demonstrate that eIF-5A is required for efficient interaction of Rev–NES with CRM1/exportin1 and that eIF-5A interacts with the nucleoporins CAN/nup214, nup153, nup98, and nup62. Quite unexpectedly, nuclear actin was also identified as an eIF-5A binding protein. We show that actin is associated with the nucleoplasmic filaments of nuclear pore complexes and is critically involved in export processes. Finally, actin- and energy-dependent nuclear export of HIV-1 Rev is reconstituted by using a novel in vitro egg extract system. In summary, our data provide evidence that actin plays an important functional role in nuclear export not only of retroviral RNAs but also of host proteins such as protein kinase inhibitor (PKI).
Key Words: eIF-5A • CRM1 • nuclear actin • nuclear export • HIV-1 Rev
© 2001 The Rockefeller University Press
Abbreviations used in this paper: CTE, constitutive transport element; eIF-5A, eukaryotic initiation factor 5A; F-actin, actin filaments; FG, phenylalanine–glycine; GFP, green fluorescent protein; GST, glutathione S-transferase; HIV-1, human immunodeficiency virus type 1; MPMV, Mason-Pfizer monkey virus; NES, nuclear export signals; NPC, nuclear pore complex; PKI, protein kinase inhibitor; RRE, Rev response element; wt, wild-type.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
|
|
