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- Bauren, G, et al.
(author)
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Demonstration of a dynamic, transcription-dependent organization of pre-mRNA splicing factors in polytene nuclei
- 1996
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In: The Journal of cell biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 133:5, s. 929-941
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Journal article (peer-reviewed)abstract
- We describe the dynamic organization of pre-mRNA splicing factors in the intact polytene nuclei of the dipteran Chironomus tentans. The snRNPs and an SR non-snRNP splicing factor are present in excess, mainly distributed throughout the interchromatin. Approximately 10% of the U2 snRNP and an SR non-snRNP splicing factor are associated with the chromosomes, highly enriched in active gene loci where they are bound to RNA. We demonstrate that the splicing factors are specifically recruited to a defined gene upon induction of transcription during physiological conditions. Concomitantly, the splicing factors leave gene loci in which transcription is turned off. We also demonstrated that upon general transcription inhibition, the splicing factors redistribute from active gene loci to the interchromatin. Our findings demonstrate the dynamic intranuclear organization of splicing factors and a tight linkage between transcription and the intranuclear organization of the splicing machinery.
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| 2. |
- Bauren, G, et al.
(author)
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Transcriptional termination in the Balbiani ring 1 gene is closely coupled to 3'-end formation and excision of the 3'-terminal intron
- 1998
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In: Genes & development. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 12:17, s. 2759-2769
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Journal article (peer-reviewed)abstract
- We have analyzed transcription termination, 3′-end formation, and excision of the 3′-terminal intron in vivo in the Balbiani ring 1 (BR1) gene and its pre-mRNA. We show that full-length RNA transcripts are evenly spaced on the gene from a position 300 bp upstream to a region 500–700 bp downstream of the polyadenylation sequence. Very few full-length transcripts and no short, cleaved, nascent transcripts could be observed downstream of this region. Pre-mRNA with 10–20 adenylate residues accumulates at the active gene and then rapidly leaves from the gene locus. Only polyadenylated pre-mRNAs could be detected in the nucleoplasm. Our results are consistent with the hypothesis that transcription termination occurs in a narrow region for the majority of transcripts, simultaneous with 3′-end formation. Excision of the 3′-terminal intron occurs before 3′-end formation in about 5% of the nascent transcripts. When transcription terminates, 3′ cleavage takes place and 10–20 adenylate residues are added, the 3′-terminal intron is excised from additionally about 75% of the pre-mRNA at the gene locus. Our data support a close temporal and spatial coupling of transcription termination and the cleavage and initial polyadenylation of 3′-end formation. Excision of the 3′-terminal intron is highly stimulated as the cleavage/polyadenylation complex assembles and 3′-end formation is initiated.
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| 3. |
- Bjork, P, et al.
(author)
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A novel conserved RNA-binding domain protein, RBD-1, is essential for ribosome biogenesis
- 2002
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In: Molecular biology of the cell. - : American Society for Cell Biology (ASCB). - 1059-1524 .- 1939-4586. ; 13:10, s. 3683-3695
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Journal article (peer-reviewed)abstract
- Synthesis of the ribosomal subunits from pre-rRNA requires a large number of trans-acting proteins and small nucleolar ribonucleoprotein particles to execute base modifications, RNA cleavages, and structural rearrangements. We have characterized a novel protein, RNA-binding domain-1 (RBD-1), that is involved in ribosome biogenesis. This protein contains six consensus RNA-binding domains and is conserved as to sequence, domain organization, and cellular location from yeast to human. RBD-1 is essential in Caenorhabditis elegans. In the dipteran Chironomus tentans, RBD-1 (Ct-RBD-1) binds pre-rRNA in vitro and anti-Ct-RBD-1 antibodies repress pre-rRNA processing in vivo. Ct-RBD-1 is mainly located in the nucleolus in an RNA polymerase I transcription-dependent manner, but it is also present in discrete foci in the interchromatin and in the cytoplasm. In cytoplasmic extracts, 20–30% of Ct-RBD-1 is associated with ribosomes and, preferentially, with the 40S ribosomal subunit. Our data suggest that RBD-1 plays a role in structurally coordinating pre-rRNA during ribosome biogenesis and that this function is conserved in all eukaryotes.
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