Izaurralde E , Jarmolowski A , Beisel C , Mattaj IW , Dreyfuss G , Fischer U .

	Figure 1. The hnRNP A1 M9 domain mediates nuclear import in Xenopus oocytes. Xenopus laevis oocytes were injected into the cytoplasm with the following in vitro translated 35S-labeled proteins: full length human hnRNP A1 (aa1-320), hnRNP A1ΔM9, a truncated form of A1 lacking the M9 domain (aa1-236), and NPLc-M9, a nucleoplasmin core–M9 fusion (A1 aa255-320), as indicated. In lanes 1–3, proteins were extracted immediately after injection and in lanes 4–6, 4 h after injection. T, C, and N indicate proteins extracted from total oocytes or after dissection from cytoplasmic or nuclear fractions, respectively. Proteins were analyzed by SDS-PAGE followed by fluorography.
	Figure 6. Inhibitors of basic NLS import differentially affect U snRNA and mRNA export. Xenopus leavis oocytes were injected into the cytoplasm with the inhibitors indicated above the lanes. As a control, oocytes were injected with PBS alone (lanes 1–6). After 1 h incubation a second microinjection was performed into the oocyte nuclei with a mixture of the following radioactively labeled RNAs: DHFR mRNA, U1ΔSm, U5ΔSm, U6Δss, and human initiator methionyl tRNA. U6Δss does not leave the nucleus and is an internal control for nuclear integrity. Synthesis of DHFR, U1ΔSm, and U5ΔSm RNAs was primed with the m7GpppG cap dinucleotide, whereas synthesis of U6Δss RNA was primed with γ-mGTP. In lanes 4–18 RNA was extracted 150 min after injection; in lanes 1–3, RNA was extracted immediately after injection. The concentration of the inhibitors in the injected samples was as indicated in Fig. 4.
	Figure 4. M9-mediated import is importin α independent. Xenopus laevis oocytes were injected into the cytoplasm with a mixture of labeled CBP80 and hnRNP A1 as indicated. In lanes 1–6, labeled proteins were diluted in PBS; in lanes 7–18 the labeled proteins were coinjected with the inhibitors indicated above the lanes. Bacterially expressed recombinant IBB (lanes 10–12) or truncated IBB (IBB trunc; lanes 7–9) were injected at a concentration of 20 mg/ml. The concentration of the BSA-NLS peptide conjugate (lanes 16–18) or of the BSA crosslinked to the reverse NLS peptide (BSA-NLSrev; lanes 13–15) was 20 mg/ml in the injection mixtures. Protein samples from total oocytes (T) or cytoplasmic (C) and nuclear (N) fractions were collected 5 h after injection in lanes 4–18 or immediately after injection in lanes 1–3. Proteins were analyzed as described in Fig. 1.
	Figure 2. M9-mediated nuclear import is saturable. In vitro translated 35S-labeled hnRNP A1 (A1) was injected into Xenopus laevis oocyte cytoplasm either without competitor (lanes 1 and 2) or with bacterially expressed GST-M9 mutant fusion (A1 aa268-305, Gly 274 mutated to Ala; GST-M9mu; lanes 3 and 4) or GST-M9 fusion (A1 aa268-305; lanes 5 and 6). The concentration of recombinant proteins in the injected samples was 10 mg/ml, and the final concentration in the oocyte is 5–10% of this value. Transport was analyzed after 5 h incubation as described in Fig. 1.
	Figure 3. Saturation of the M9 import pathway does not interfere with NLS-mediated import. In vitro translated 35S-labeled PKNLS and PK-M9 (A1 aa268-305) were injected into the cytoplasm of Xenopus laevis oocytes either without competitor (lanes 1 and 2 and 7 and 8) or with bacterially expressed recombinant GST-M9 (lanes 5 and 6 and 11 and 12) or GST-M9mu (lanes 3 and 4 and 9 and 10). Lanes 13 and 14 show in vitro translated PK-NLS and PK-M9, respectively. The concentration of recombinant proteins in the injected samples was 10 mg/ml. Transport was analyzed 5 h after injection as described in Fig. 1.
	Figure 5. Saturation of M9mediated import does not interfere with nuclear uptake of U snRNAs. 32pCp-labeled U1, U2, U4, and U5 snRNAs were injected into the cytoplasm of oocytes either without competitor (lanes 1–5) or together with 10 mg/ml of recombinant GST-M9mu (lanes 6–10) or GST-M9 (lanes 11–15). Oocytes were dissected 3 or 12 h after injection as indicated, and RNA was analyzed on denaturing polyacrylamide gels. Lanes 1, 6, and 11 were loaded with RNA extracted from total oocytes immediately after injection.

Bataillé, Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process. 1990, Pubmed, Xenbase

Bataillé, Cytoplasmic transport of ribosomal subunits microinjected into the Xenopus laevis oocyte nucleus: a generalized, facilitated process. 1990, Pubmed , Xenbase
Bogerd, Protein sequence requirements for function of the human T-cell leukemia virus type 1 Rex nuclear export signal delineated by a novel in vivo randomization-selection assay. 1996, Pubmed
Bossie, A mutant nuclear protein with similarity to RNA binding proteins interferes with nuclear import in yeast. 1992, Pubmed
Dingwall, Nuclear targeting sequences--a consensus? 1991, Pubmed
Dingwall, A polypeptide domain that specifies migration of nucleoplasmin into the nucleus. 1982, Pubmed , Xenbase
Dreyfuss, hnRNP proteins and the biogenesis of mRNA. 1993, Pubmed
Fischer, Nucleo-cytoplasmic transport of U snRNPs: definition of a nuclear location signal in the Sm core domain that binds a transport receptor independently of the m3G cap. 1993, Pubmed , Xenbase
Fischer, Evidence that HIV-1 Rev directly promotes the nuclear export of unspliced RNA. 1994, Pubmed , Xenbase
Fischer, The HIV-1 Rev activation domain is a nuclear export signal that accesses an export pathway used by specific cellular RNAs. 1995, Pubmed
Fischer, Diversity in the signals required for nuclear accumulation of U snRNPs and variety in the pathways of nuclear transport. 1991, Pubmed , Xenbase
Fischer, An essential signaling role for the m3G cap in the transport of U1 snRNP to the nucleus. 1990, Pubmed , Xenbase
Flach, A yeast RNA-binding protein shuttles between the nucleus and the cytoplasm. 1994, Pubmed
Gerace, Nuclear export signals and the fast track to the cytoplasm. 1995, Pubmed
Goldfarb, Synthetic peptides as nuclear localization signals. , Pubmed , Xenbase
Görlich, Importin provides a link between nuclear protein import and U snRNA export. 1996, Pubmed , Xenbase
Görlich, A 41 amino acid motif in importin-alpha confers binding to importin-beta and hence transit into the nucleus. 1996, Pubmed , Xenbase
Görlich, Nucleocytoplasmic transport. 1996, Pubmed
Hamm, The trimethylguanosine cap structure of U1 snRNA is a component of a bipartite nuclear targeting signal. 1990, Pubmed , Xenbase
Izaurralde, A nuclear cap binding protein complex involved in pre-mRNA splicing. 1994, Pubmed , Xenbase
Izaurralde, A cap-binding protein complex mediating U snRNA export. 1995, Pubmed , Xenbase
Izaurralde, RNA export. 1995, Pubmed
Izaurralde, Nuclear localization of a cap-binding protein complex. 1995, Pubmed , Xenbase
Jarmolowski, The determinants for Sm protein binding to Xenopus U1 and U5 snRNAs are complex and non-identical. 1993, Pubmed , Xenbase
Jarmolowski, Nuclear export of different classes of RNA is mediated by specific factors. 1994, Pubmed , Xenbase
Kalland, The human immunodeficiency virus type 1 Rev protein shuttles between the cytoplasm and nuclear compartments. 1994, Pubmed
Kambach, Intracellular distribution of the U1A protein depends on active transport and nuclear binding to U1 snRNA. 1992, Pubmed , Xenbase
Kataoka, Cloning of a complementary DNA encoding an 80 kilodalton nuclear cap binding protein. 1994, Pubmed
Lee, A protein that shuttles between the nucleus and the cytoplasm is an important mediator of RNA export. 1996, Pubmed
Melchior, Inhibition of nuclear protein import by nonhydrolyzable analogues of GTP and identification of the small GTPase Ran/TC4 as an essential transport factor. 1993, Pubmed
Melchior, Mechanisms of nuclear protein import. 1995, Pubmed
Meyer, The HIV-1 Rev trans-activator shuttles between the nucleus and the cytoplasm. 1994, Pubmed
Michael, A nuclear export signal in hnRNP A1: a signal-mediated, temperature-dependent nuclear protein export pathway. 1995, Pubmed
Michael, Signal sequences that target nuclear import and nuclear export of pre-mRNA-binding proteins. 1995, Pubmed
Michaud, Microinjected U snRNAs are imported to oocyte nuclei via the nuclear pore complex by three distinguishable targeting pathways. 1992, Pubmed , Xenbase
Michaud, Multiple pathways in nuclear transport: the import of U2 snRNP occurs by a novel kinetic pathway. 1991, Pubmed , Xenbase
Moore, The GTP-binding protein Ran/TC4 is required for protein import into the nucleus. 1993, Pubmed , Xenbase
Moore, Purification of a Ran-interacting protein that is required for protein import into the nucleus. 1994, Pubmed , Xenbase
Newmeyer, Nuclear import can be separated into distinct steps in vitro: nuclear pore binding and translocation. 1988, Pubmed , Xenbase
Paschal, Identification of NTF2, a cytosolic factor for nuclear import that interacts with nuclear pore complex protein p62. 1995, Pubmed
Piñol-Roma, Shuttling of pre-mRNA binding proteins between nucleus and cytoplasm. 1992, Pubmed , Xenbase
Piñol-Roma, hnRNP proteins: localization and transport between the nucleus and the cytoplasm. 1993, Pubmed
Piñol-Roma, Transcription-dependent and transcription-independent nuclear transport of hnRNP proteins. 1991, Pubmed
Pollard, A novel receptor-mediated nuclear protein import pathway. 1996, Pubmed
Powers, Cytosolic factors in nuclear transport: what's importin? 1994, Pubmed
Richardson, Nuclear protein migration involves two steps: rapid binding at the nuclear envelope followed by slower translocation through nuclear pores. 1988, Pubmed , Xenbase
Russell, Yeast Nop3p has structural and functional similarities to mammalian pre-mRNA binding proteins. 1995, Pubmed
Sanger, DNA sequencing with chain-terminating inhibitors. 1977, Pubmed
Singleton, A yeast protein that bidirectionally affects nucleocytoplasmic transport. 1995, Pubmed
Siomi, A nuclear localization domain in the hnRNP A1 protein. 1995, Pubmed
van Zee, A cytoplasmically anchored nuclear protein interferes specifically with the import of nuclear proteins but not U1 snRNA. 1993, Pubmed
Visa, A pre-mRNA-binding protein accompanies the RNA from the gene through the nuclear pores and into polysomes. 1996, Pubmed
Visa, A nuclear cap-binding complex binds Balbiani ring pre-mRNA cotranscriptionally and accompanies the ribonucleoprotein particle during nuclear export. 1996, Pubmed
Weighardt, Nucleo-cytoplasmic distribution of human hnRNP proteins: a search for the targeting domains in hnRNP A1. 1995, Pubmed
Weis, The conserved amino-terminal domain of hSRP1 alpha is essential for nuclear protein import. 1996, Pubmed
Wen, Identification of a signal for rapid export of proteins from the nucleus. 1995, Pubmed
Wilson, Characterization of nuclear polyadenylated RNA-binding proteins in Saccharomyces cerevisiae. 1994, Pubmed
Zasloff, tRNA transport from the nucleus in a eukaryotic cell: carrier-mediated translocation process. 1983, Pubmed , Xenbase