scholarly journals Cajal body surveillance of U snRNA export complex assembly

2010 ◽  
Vol 190 (4) ◽  
pp. 603-612 ◽  
Author(s):  
Tatsuya Suzuki ◽  
Hiroto Izumi ◽  
Mutsuhito Ohno
Keyword(s):  
Xenopus Laevis ◽  
Dominant Negative ◽  
Cajal Body ◽  
Cajal Bodies ◽  
Xenopus Laevis Oocyte ◽  
Small Nuclear Rna ◽  
Body Surveillance ◽  
Complex Assembly ◽  
Nuclear Rna ◽  
Rna Export

Phosphorylated adaptor for RNA export (PHAX) is the key export mediator for spliceosomal U small nuclear RNA (snRNA) precursors in metazoa. PHAX is enriched in Cajal bodies (CBs), nuclear subdomains involved in the biogenesis of small ribonucleoproteins. However, CBs’ role in U snRNA export has not been demonstrated. In this study, we show that U snRNA precursors microinjected into Xenopus laevis oocyte nuclei temporarily concentrate in CBs but gradually decrease as RNA export proceeds. Inhibition of PHAX activity by the coinjection of a specific anti-PHAX antibody or a dominant-negative PHAX mutant inhibits U snRNA export and simultaneously enhances accumulation of U snRNA precursors in CBs, indicating that U snRNAs transit through CBs before export and that binding to PHAX is required for efficient exit of U snRNAs from CBs. Similar results were obtained with U snRNAs transcribed from microinjected genes. These results reveal a novel function for CBs, which ensure that U snRNA precursors are properly bound by PHAX.

Splicing of Xenopus laevis ribosomal protein RNAs is inhibited in vivo by antisera to ribonucleoproteins containing U1 small nuclear RNA

1984 ◽  
Vol 180 (4) ◽  
pp. 1173-1178 ◽  
Author(s):  
Irene Bozzoni ◽  
Flavia Annesi ◽  
Elena Beccari ◽  
Paola Fragapane ◽  
Paola Pierandrei-Amaldi ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Ribosomal Protein ◽  
Small Nuclear Rna ◽  
Nuclear Rna

scholarly journals The Drosophila melanogaster Cajal body

2006 ◽  
Vol 172 (6) ◽  
pp. 875-884 ◽  
Author(s):  
Ji-Long Liu ◽  
Christine Murphy ◽  
Michael Buszczak ◽  
Sarah Clatterbuck ◽  
Robyn Goodman ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Motor Neurons ◽  
Nuclear Body ◽  
Nuclear Bodies ◽  
Cajal Body ◽  
Small Nuclear Rna ◽  
Nuclear Rna ◽  
Survival Of Motor Neurons ◽  
And Function ◽  
Histone Locus

Cajal bodies (CBs) are nuclear organelles that are usually identified by the marker protein p80-coilin. Because no orthologue of coilin is known in Drosophila melanogaster, we identified D. melanogaster CBs using probes for other components that are relatively diagnostic for CBs in vertebrate cells. U85 small CB–specific RNA, U2 small nuclear RNA, the survival of motor neurons protein, and fibrillarin occur together in a nuclear body that is closely associated with the nucleolus. Based on its similarity to CBs in other organisms, we refer to this structure as the D. melanogaster CB. Surprisingly, the D. melanogaster U7 small nuclear RNP resides in a separate nuclear body, which we call the histone locus body (HLB). The HLB is invariably colocalized with the histone gene locus. Thus, canonical CB components are distributed into at least two nuclear bodies in D. melanogaster. The identification of these nuclear bodies now permits a broad range of questions to be asked about CB structure and function in a genetically tractable organism.

Nuclear processing of the 3'-terminal nucleotides of pre-U1 RNA in Xenopus laevis oocytes

1992 ◽  
Vol 12 (4) ◽  
pp. 1553-1560
Author(s):  
H Yang ◽  
M L Moss ◽  
E Lund ◽  
J E Dahlberg
Keyword(s):  
Xenopus Laevis ◽  
Micrococcal Nuclease ◽  
Xenopus Laevis Oocytes ◽  
Small Nuclear Rna ◽  
Trypsin Treatment ◽  
Differential Processing ◽  
Nuclear Extracts ◽  
Nuclear Rna ◽  
Processing Activity ◽  
Nuclear Processing

U1 small nuclear RNA is synthesized as a precursor with several extra nucleotides at its 3' end. We show that in Xenopus laevis oocytes, removal of the terminal two nucleotides occurs after the RNA has transited through the cytoplasm and returned to the nucleus. The activity is controlled by an inhibitor of processing, which we call TPI, for 3'-terminal processing inhibitor. This inhibitor is sensitive to both micrococcal nuclease and trypsin treatment, indicating that it is a nucleoprotein. TPI inhibits the 3' processing of pre-U1 RNAs that have 5' ends containing m7G caps but not mature m2,2,7G caps; this finding suggests that TPI interacts directly or indirectly with the 5' end of pre-U1 RNA. The inhibition of processing by TPI, almost complete at 19 degrees C, is reversibly inactivated at slightly higher temperatures. TPI activity is solely in the soluble fraction of oocyte nuclear extracts, in contrast to the 3'-terminal processing activity, which is present in both the particulate and soluble fractions. We propose that the differential processing of the 3'-terminal nucleotides of pre-U1 RNA after its return from the cytoplasm, but not before its exit from the nucleus, may be due to the association of TPI with the m7G cap on the newly synthesized pre-U1 RNA.

scholarly journals All Small Nuclear RNAs (snRNAs) of the [U4/U6.U5] Tri-snRNP Localize to Nucleoli; Identification of the Nucleolar Localization Element of U6 snRNA

2002 ◽  
Vol 13 (9) ◽  
pp. 3123-3137 ◽  
Author(s):  
Susan A. Gerbi ◽  
Thilo Sascha Lange
Keyword(s):  
Direct Interaction ◽  
Cajal Bodies ◽  
Nucleolar Localization ◽  
Small Nuclear Rna ◽  
U6 Snrna ◽  
La Protein ◽  
Small Nuclear Rnas ◽  
Nuclear Rna ◽  
Localization Elements ◽  
Localization Element

Previously, we showed that spliceosomal U6 small nuclear RNA (snRNA) transiently passes through the nucleolus. Herein, we report that all individual snRNAs of the [U4/U6.U5] tri-snRNP localize to nucleoli, demonstrated by fluorescence microscopy of nucleolar preparations after injection of fluorescein-labeled snRNA into Xenopus oocyte nuclei. Nucleolar localization of U6 is independent from [U4/U6] snRNP formation since sites of direct interaction of U6 snRNA with U4 snRNA are not nucleolar localization elements. Among all regions in U6, the only one required for nucleolar localization is its 3′ end, which associates with the La protein and subsequently during maturation of U6 is bound by Lsm proteins. This 3′-nucleolar localization element of U6 is both essential and sufficient for nucleolar localization and also required for localization to Cajal bodies. Conversion of the 3′ hydroxyl of U6 snRNA to a 3′ phosphate prevents association with the La protein but does not affect U6 localization to nucleoli or Cajal bodies.

scholarly journals Nuclear processing of the 3'-terminal nucleotides of pre-U1 RNA in Xenopus laevis oocytes.

1992 ◽  
Vol 12 (4) ◽  
pp. 1553-1560 ◽  
Author(s):  
H Yang ◽  
M L Moss ◽  
E Lund ◽  
J E Dahlberg
Keyword(s):  
Xenopus Laevis ◽  
Micrococcal Nuclease ◽  
Xenopus Laevis Oocytes ◽  
Small Nuclear Rna ◽  
Trypsin Treatment ◽  
Differential Processing ◽  
Nuclear Extracts ◽  
Nuclear Rna ◽  
Processing Activity ◽  
Nuclear Processing

U1 small nuclear RNA is synthesized as a precursor with several extra nucleotides at its 3' end. We show that in Xenopus laevis oocytes, removal of the terminal two nucleotides occurs after the RNA has transited through the cytoplasm and returned to the nucleus. The activity is controlled by an inhibitor of processing, which we call TPI, for 3'-terminal processing inhibitor. This inhibitor is sensitive to both micrococcal nuclease and trypsin treatment, indicating that it is a nucleoprotein. TPI inhibits the 3' processing of pre-U1 RNAs that have 5' ends containing m7G caps but not mature m2,2,7G caps; this finding suggests that TPI interacts directly or indirectly with the 5' end of pre-U1 RNA. The inhibition of processing by TPI, almost complete at 19 degrees C, is reversibly inactivated at slightly higher temperatures. TPI activity is solely in the soluble fraction of oocyte nuclear extracts, in contrast to the 3'-terminal processing activity, which is present in both the particulate and soluble fractions. We propose that the differential processing of the 3'-terminal nucleotides of pre-U1 RNA after its return from the cytoplasm, but not before its exit from the nucleus, may be due to the association of TPI with the m7G cap on the newly synthesized pre-U1 RNA.

Nucleocytoplasmic transport and processing of small nuclear RNA precursors

1990 ◽  
Vol 10 (7) ◽  
pp. 3365-3375
Author(s):  
H E Neuman de Vegvar ◽  
J E Dahlberg
Keyword(s):  
Xenopus Laevis ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Nucleocytoplasmic Transport ◽  
Xenopus Laevis Oocytes ◽  
Small Nuclear Rna ◽  
The Past ◽  
Nuclear Rna

We have analyzed the structures and locations of small nuclear RNA (snRNA) precursors at various stages in their synthesis and maturation. In the nuclei of pulse-labeled Xenopus laevis oocytes, we detected snRNAs that were longer than their mature forms at their 3' ends by up to 10 nucleotides. Analysis of the 5' caps of these RNAs and pulse-chase experiments showed that these nuclear snRNAs were precursors of the cytoplasmic pre-snRNAs that have been observed in the past. Synthesis of pre-snRNAs was not abolished by wheat germ agglutinin, which inhibits export of the pre-snRNAs from the nucleus, indicating that synthesis of these RNAs is not obligatorily coupled to their export. Newly synthesized U1 RNAs could be exported from the nucleus regardless of the length of the 3' extension, but pre-U1 RNAs that were elongated at their 3' ends by more than about 10 nucleotides were poor substrates for trimming in the cytoplasm. The structure at the 3' end was critical for subsequent transport of the RNA back to the nucleus. This requirement ensures that truncated and incompletely processed U1 RNAs are excluded from the nucleus.

scholarly journals Nucleocytoplasmic transport and processing of small nuclear RNA precursors.

1990 ◽  
Vol 10 (7) ◽  
pp. 3365-3375 ◽  
Author(s):  
H E Neuman de Vegvar ◽  
J E Dahlberg
Keyword(s):  
Xenopus Laevis ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Nucleocytoplasmic Transport ◽  
Xenopus Laevis Oocytes ◽  
Small Nuclear Rna ◽  
The Past ◽  
Nuclear Rna

We have analyzed the structures and locations of small nuclear RNA (snRNA) precursors at various stages in their synthesis and maturation. In the nuclei of pulse-labeled Xenopus laevis oocytes, we detected snRNAs that were longer than their mature forms at their 3' ends by up to 10 nucleotides. Analysis of the 5' caps of these RNAs and pulse-chase experiments showed that these nuclear snRNAs were precursors of the cytoplasmic pre-snRNAs that have been observed in the past. Synthesis of pre-snRNAs was not abolished by wheat germ agglutinin, which inhibits export of the pre-snRNAs from the nucleus, indicating that synthesis of these RNAs is not obligatorily coupled to their export. Newly synthesized U1 RNAs could be exported from the nucleus regardless of the length of the 3' extension, but pre-U1 RNAs that were elongated at their 3' ends by more than about 10 nucleotides were poor substrates for trimming in the cytoplasm. The structure at the 3' end was critical for subsequent transport of the RNA back to the nucleus. This requirement ensures that truncated and incompletely processed U1 RNAs are excluded from the nucleus.

7SK small nuclear RNA inhibits cancer cell proliferation through apoptosis induction

Tumor Biology ◽  
2014 ◽  
Vol 36 (4) ◽  
pp. 2809-2814 ◽  
Author(s):  
Farid Keramati ◽  
Ehsan Seyedjafari ◽  
Parviz Fallah ◽  
Masoud Soleimani ◽  
Hossein Ghanbarian
Keyword(s):  
Cell Proliferation ◽  
Cancer Cell ◽  
Cancer Cell Proliferation ◽  
Small Nuclear Rna ◽  
Apoptosis Induction ◽  
Nuclear Rna

scholarly journals Involvement of single-stranded tails in homologous recombination of DNA injected into Xenopus laevis oocyte nuclei.

1991 ◽  
Vol 11 (6) ◽  
pp. 3268-3277 ◽  
Author(s):  
E Maryon ◽  
D Carroll
Keyword(s):  
Homologous Recombination ◽  
Xenopus Laevis ◽  
Gel Electrophoresis ◽  
Xenopus Laevis Oocyte ◽  
Molecular Models ◽  
Mixed Substrates ◽  
Two Dimensional Gel Electrophoresis ◽  
Recombination Pathway ◽  
Made In

Homologous recombination of DNA molecules injected into Xenopus laevis oocyte nuclei is extremely efficient when those molecules are linear and have overlapping homologous ends. It was previously shown that a 5'----3' exonuclease activity in oocytes attacks injected linear DNAs and leaves them with single-stranded 3' tails. We tested the hypothesis that such tailed molecules are early intermediates on the pathway to recombination products. Substrates with 3' tails were made in vitro and injected into oocytes, where they recombined rapidly and efficiently. In experiments with mixed substrates, molecules with 3' tails entered recombination intermediates and products more rapidly than did molecules with flush ends. Molecules endowed in vitro with 5' tails also recombined efficiently in oocytes, but their rate was not faster than for flush-ended substrates. In most cases, the 5' tails served as templates for resynthesis of the 3' strands, regenerating duplex ends which then entered the normal recombination pathway. In oocytes from one animal, some of the 5' tails were removed, and this was exacerbated when resynthesis was partially blocked. Analysis by two-dimensional gel electrophoresis of recombination intermediates from 5'-tailed substrates confirmed that they had acquired 3' tails as a result of the action of the 5'----3' exonuclease. These results demonstrate that homologous recombination in oocytes proceeds via a pathway that involves single-stranded 3' tails. Molecular models incorporating this feature are discussed.

Isolation of a potato U6 small nuclear RNA gene

1991 ◽  
Vol 19 (3) ◽  
pp. 340S-340S
Author(s):  
YUNQIAN HU ◽  
JOHN W. S. BROWN ◽  
ROBBIE WAUGH ◽  
PHILIP C. TURNER
Keyword(s):  
Small Nuclear Rna ◽  
Nuclear Rna
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