The vertebrate GLFG nucleoporin, Nup98, is an essential component of multiple RNA export pathways.
The 97-kD O-linked glycoprotein, Nup98, is a component of the Xenopus laevis nuclear pore complex and the only vertebrate GLFG nucleoporin identified (Powers, M.A., C. Macauley, F. Masiarz, and D.J. Forbes. 1995. J. Cell Biol. 128:721-736). We have investigated possible roles of xNup98 in the nucleocytoplasmic transport of proteins and RNAs by analyzing the consequences of injecting monospecific polyclonal antibodies to xNup98 into X. laevis oocytes. We show here that nuclear injection of anti-xNup98 inhibited the export of multiple classes of RNAs, including snRNAs, 5S RNA, large ribosomal RNAs, and mRNA. In contrast, the export of tRNA was unaffected. Injection of anti-xNup98 into the oocyte cytoplasm had no effect on export of any of the RNAs. Significantly, nuclear injection of anti-xNup98 antibodies did not inhibit import of either karyophilic proteins or snRNPs. This latter result is in agreement with our previous finding that Nup98 is not an essential element of the protein import pathway. Thus, Nup98 plays a role specifically in RNA export from the nucleus, and it appears to be an essential component of multiple RNA export pathways.
Powers
M A
MA
Department of Biology, University of California at San Diego, La Jolla 92093-0347, USA.
Forbes
D J
DJ
Dahlberg
J E
JE
Lund
E
E
D000818:Animals; D000906:Antibodies; D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism*; D008565:Membrane Proteins / Q000276:immunology / Q000502:physiology*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D009865:Oocytes; D011233:Precipitin Tests; D012313:RNA / Q000378:metabolism*; D012315:RNA Caps / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D012339:RNA, Ribosomal, 28S / Q000378:metabolism; D012341:RNA, Ribosomal, 5S / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D014982:Xenopus laevis
D000906:Antibodies; D008565:Membrane Proteins; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D012315:RNA Caps; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D012341:RNA, Ribosomal, 5S; D012342:RNA, Small Nuclear; C093350:nuclear pore complex protein 98; D012313:RNA; D012343:RNA, Transfer