Cajal bodies are evolutionarily conserved nuclear organelles that are believed to play a central role in assembly of RNA transcription and processing complexes. Although knowledge of Cajal body composition and behavior has greatly expanded in recent years, little is known about the molecules and mechanisms that lead to the formation of these organelles in the nucleus. The Xenopus oocyte nucleus or germinal vesicle is an excellent model system for the study of Cajal bodies, because it is easy to manipulate and it contains 50-100 Cajal bodies with diameters up to 10 microm. In this study we show that numerous mini-Cajal bodies (less than 2 microm in diameter) form in the germinal vesicle after oocytes recover from heat shock. The mechanism for heat shock induction of mini-Cajal bodies is independent of U7 snRNA and does not require transcription or import of newly translated proteins from the cytoplasm. We suggest that Cajal bodies originate by self-organization of preformed components, preferentially on the surface of B-snurposomes.
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http://dx.doi.org/10.1242/jcs.115.10.2011 | DOI Listing |
Biochim Biophys Acta Gen Subj
January 2025
Graduate School of Life Science, Hokkaido University, Sapporo 060-0812, Japan; Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Biomolecular condensates like U-bodies are specialized cellular structures formed through multivalent interactions among intrinsically disordered regions. U-bodies sequester small nuclear ribonucleoprotein complexes (snRNPs) in the cytoplasm, and their formation in mammalian cells depends on stress conditions. Because of their location adjacent to P-bodies, U-bodies have been considered potential sites for snRNP storage or turnover.
View Article and Find Full Text PDFJ Cell Biol
February 2025
Department of Biochemistry, University of Colorado, Boulder, CO, USA.
Cajal bodies are essential sites for the biogenesis of small nuclear and nucleolar ribonucleoproteins. In this issue, Courvan and Parker discuss new work from Neugebauer and colleagues (https://doi.org/10.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Cellular activity is spatially organized across different organelles. While several structures are well-characterized, many organelles have unknown roles. Profiling biomolecular composition is key to understanding function but is difficult to achieve in the context of small, dynamic structures.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.
The proteins SFPQ (splicing Factor Proline/Glutamine rich) and NONO (non-POU domain-containing octamer-binding protein) are mammalian members of the Drosophila Behaviour/Human Splicing (DBHS) protein family, which share 76% sequence identity in their conserved 320 amino acid DBHS domain. SFPQ and NONO are involved in all steps of post-transcriptional regulation and are primarily located in mammalian paraspeckles: liquid phase-separated, ribonucleoprotein sub-nuclear bodies templated by NEAT1 long non-coding RNA. A combination of structured and low-complexity regions provide polyvalent interaction interfaces that facilitate homo- and heterodimerisation, polymerisation, interactions with oligonucleotides, mRNA, long non-coding RNA, and liquid phase-separation, all of which have been implicated in cellular homeostasis and neurological diseases including neuroblastoma.
View Article and Find Full Text PDFJ Cell Sci
December 2024
Department of Cell and Molecular Biology, The University of Mississippi Medical Center, Jackson, MS 39216-4505, USA.
Cajal bodies (CBs) are membraneless organelles whose mechanism of formation is still not fully understood. Many proteins contribute to the formation of CBs, including Nopp140 (NOLC1), WRAP53 and coilin. Coilin is modified on multiple different lysine residues by SUMO, the small ubiquitin-like modifier.
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