Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Nuclear transport of U1 snRNP in somatic cells: differences in signal requirement compared with Xenopus laevis oocytes.
Fischer U
,
Heinrich J
,
van Zee K
,
Fanning E
,
Lührmann R
.
???displayArticle.abstract???
The signal requirement for the nuclear import of U1 RNA in somatic cells from different species was investigated by microinjection of both digoxygenin-labeled wild type and mutant U1 RNA molecules and in vitro reconstituted U1 snRNPs. U1 RNA was shown to be targeted to the nucleus by a temperature-dependent process that requires the prior assembly of RNPs from the common proteins and the microinjected RNA. Competition in the cell between immunoaffinity-purified U1 snRNPs and digoxygenin-labeled U1 snRNPs reconstituted in vitro showed that the transport is saturable and should therefore be a mediated process. The transport of a karyophilic protein under the same conditions was not affected, indicating the existence of a U snRNP-specific transport pathway in somatic cells, as already seen in the Xenopus laevis oocyte system. Surprisingly, the signal requirement for nuclear transport of U1 snRNP was found to differ between oocytes and somatic cells from mouse, monkey and Xenopus, in that the m3GGpppG-cap is no longer an essential signaling component in somatic cells. However, as shown by investigation of the transport kinetics of m3GpppG- and ApppG-capped U1 snRNPs, the m3GpppG-cap accelerates the rate of U1 snRNP import significantly indicating that it has retained a signaling role for nuclear targeting of U1 snRNP in somatic cells. Moreover, our data strongly suggest that cell specific rather than species specific differences account for the differential m3G-cap requirement in nuclear import of U1 snRNPs.
Branlant,
U2 RNA shares a structural domain with U1, U4, and U5 RNAs.
1982, Pubmed
Branlant,
U2 RNA shares a structural domain with U1, U4, and U5 RNAs.
1982,
Pubmed
Carmo-Fonseca,
In vivo detection of snRNP-rich organelles in the nuclei of mammalian cells.
1991,
Pubmed
Carmo-Fonseca,
Mammalian nuclei contain foci which are highly enriched in components of the pre-mRNA splicing machinery.
1991,
Pubmed
De Robertis,
Nucleocytoplasmic segregation of proteins and RNAs.
1983,
Pubmed
Dingwall,
Nuclear targeting sequences--a consensus?
1991,
Pubmed
Dingwall,
The nuclear membrane.
1992,
Pubmed
Feldherr,
Movement of a karyophilic protein through the nuclear pores of oocytes.
1984,
Pubmed
,
Xenbase
Fischer,
An essential signaling role for the m3G cap in the transport of U1 snRNP to the nucleus.
1990,
Pubmed
,
Xenbase
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,
Diversity in the signals required for nuclear accumulation of U snRNPs and variety in the pathways of nuclear transport.
1991,
Pubmed
,
Xenbase
Fischer-Fantuzzi,
Cell-dependent efficiency of reiterated nuclear signals in a mutant simian virus 40 oncoprotein targeted to the nucleus.
1988,
Pubmed
Forbes,
Structure and function of the nuclear pore complex.
1992,
Pubmed
,
Xenbase
Garcia-Bustos,
Nuclear protein localization.
1991,
Pubmed
Goldfarb,
Synthetic peptides as nuclear localization signals.
,
Pubmed
,
Xenbase
Graessmann,
Microinjection of early SV40 DNA fragments and T antigen.
1980,
Pubmed
Hamm,
The trimethylguanosine cap structure of U1 snRNA is a component of a bipartite nuclear targeting signal.
1990,
Pubmed
,
Xenbase
Jantsch,
Assembly and localization of the U1-specific snRNP C protein in the amphibian oocyte.
1992,
Pubmed
,
Xenbase
Jarmolowski,
The determinants for Sm protein binding to Xenopus U1 and U5 snRNAs are complex and non-identical.
1993,
Pubmed
,
Xenbase
Kalderon,
Sequence requirements for nuclear location of simian virus 40 large-T antigen.
,
Pubmed
Kambach,
Intracellular distribution of the U1A protein depends on active transport and nuclear binding to U1 snRNA.
1992,
Pubmed
,
Xenbase
Kastner,
Electron microscopy of small nuclear ribonucleoprotein (snRNP) particles U2 and U5: evidence for a common structure-determining principle in the major U snRNP family.
1990,
Pubmed
Kleinschmidt,
RNA processing and ribonucleoprotein assembly studied in vivo by RNA transfection.
1990,
Pubmed
Lanford,
Induction of nuclear transport with a synthetic peptide homologous to the SV40 T antigen transport signal.
1986,
Pubmed
Lanford,
Construction and characterization of an SV40 mutant defective in nuclear transport of T antigen.
1984,
Pubmed
Lerner,
Monoclonal antibodies to nucleic acid-containing cellular constituents: probes for molecular biology and autoimmune disease.
1981,
Pubmed
,
Xenbase
Liautard,
Structural organization of ribonucleoproteins containing small nuclear RNAs from HeLa cells. Proteins interact closely with a similar structural domain of U1, U2, U4 and U5 small nuclear RNAs.
1982,
Pubmed
Lührmann,
Structure of spliceosomal snRNPs and their role in pre-mRNA splicing.
1990,
Pubmed
Marshallsay,
In vitro nuclear import of snRNPs: cytosolic factors mediate m3G-cap dependence of U1 and U2 snRNP transport.
1994,
Pubmed
,
Xenbase
Mattaj,
Nuclear segregation of U2 snRNA requires binding of specific snRNP proteins.
1985,
Pubmed
,
Xenbase
Mattaj,
Cap trimethylation of U snRNA is cytoplasmic and dependent on U snRNP protein binding.
1986,
Pubmed
,
Xenbase
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
Newmeyer,
Nuclear import can be separated into distinct steps in vitro: nuclear pore binding and translocation.
1988,
Pubmed
,
Xenbase
Newmeyer,
An N-ethylmaleimide-sensitive cytosolic factor necessary for nuclear protein import: requirement in signal-mediated binding to the nuclear pore.
1990,
Pubmed
,
Xenbase
Nigg,
Nuclear import-export: in search of signals and mechanisms.
1991,
Pubmed
Richardson,
Nuclear protein migration involves two steps: rapid binding at the nuclear envelope followed by slower translocation through nuclear pores.
1988,
Pubmed
,
Xenbase
Rihs,
Nuclear transport kinetics depend on phosphorylation-site-containing sequences flanking the karyophilic signal of the Simian virus 40 T-antigen.
1989,
Pubmed
Robbins,
Two interdependent basic domains in nucleoplasmin nuclear targeting sequence: identification of a class of bipartite nuclear targeting sequence.
1991,
Pubmed
,
Xenbase
Silver,
How proteins enter the nucleus.
1991,
Pubmed
Slavicek,
A karyophilic signal sequence in adenovirus type 5 E1A is functional in Xenopus oocytes but not in somatic cells.
1989,
Pubmed
,
Xenbase
Standiford,
Analysis of a developmentally regulated nuclear localization signal in Xenopus.
1992,
Pubmed
,
Xenbase
van Zee,
A cytoplasmically anchored nuclear protein interferes specifically with the import of nuclear proteins but not U1 snRNA.
1993,
Pubmed
