nucleolus Dotaz Zobrazit nápovědu
The nucleolus is a nuclear compartment and represents the most obvious and clearly differentiated nuclear structure seen in the microscope. Within nucleoli most events of ribosome biogenesis, such as ribosomal RNA synthesis, processing, and ribosome subunit assembly, take place. Several lines of evidence now show that the nucleolus has also numerous non-ribosomal functions. This review is focused on the recent progress in our knowledge of how to correlate the known biochemical processes taking place in the nucleolus with nucleolar structures observed in the microscope. We still lack detailed enough information to understand fully the organization and regulation of the processes taking place in the nucleolar sub-structures. However, the present power of microscopy techniques should allow for an in situ description of the organization of nucleolar processes at the molecular level in the years to come.
- MeSH
- buněčné jadérko metabolismus ultrastruktura MeSH
- elektronová mikroskopie MeSH
- financování organizované MeSH
- lidé MeSH
- posttranskripční úpravy RNA MeSH
- ribozomy metabolismus ultrastruktura MeSH
- RNA ribozomální metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- přehledy MeSH
- MeSH
- histocytochemie MeSH
The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance.
- MeSH
- Arabidopsis MeSH
- buněčné jadérko metabolismus MeSH
- exprese genu * MeSH
- fosfoproteiny metabolismus MeSH
- genetická transkripce genetika MeSH
- genom rostlinný * MeSH
- heterochromatin genetika metabolismus MeSH
- proteiny vázající RNA metabolismus MeSH
- ribozomální DNA genetika MeSH
- RNA ribozomální metabolismus MeSH
- telomery metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
The nucleolus is the most obvious and clearly differentiated nuclear sub-compartment. It is where ribosome biogenesis takes place, but it is becoming clear that the nucleolus also has non-ribosomal functions. In this review we discuss recent progress in our understanding of how both ribosome biosynthesis and some non-ribosomal functions relate to observable nucleolar structure. We still do not have detailed enough information about the in situ organization of the various processes taking place in the nucleolus. However, the present power of light and electron microscopy techniques means that a description of the organization of nucleolar processes at the molecular level is now achievable, and the time is ripe for such an effort.
- MeSH
- biologické modely MeSH
- buněčné jadérko metabolismus ultrastruktura MeSH
- elektronová mikroskopie metody MeSH
- financování organizované MeSH
- geny rRNA MeSH
- jaderné proteiny metabolismus MeSH
- regulace genové exprese MeSH
- ribozomy metabolismus MeSH
- RNA-polymerasa I metabolismus MeSH
- transport RNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- přehledy MeSH
The oocyte GV/GVs (germinal vesicle/germinal vesicles) and zygot PN/PNs (pronucleus/pronuclei) of some mammals contain clearly visible nucleoli which exhibit an atypical morphological structure. These nucleoli (NCLs) can be relatively easily manipulated, i.e. removed from GVs/PNs or eventually transferred into another oocyte/zygote. Thus, with the help of micromanipulation techniques it was possible to uncover the real function(s) they play in processes of oocyte maturation and early embryonic development. The purpose of our review is to describe briefly the micromanipulation techniques that can be used for oocyte/zygote nucleoli manipulation. Moreover, we present some examples of results that were obtained in nucleolus manipulation experiments.
- MeSH
- buněčné jadérko metabolismus transplantace MeSH
- mikromanipulace metody MeSH
- myši MeSH
- oocyty cytologie účinky léků MeSH
- partenogeneze MeSH
- prasata MeSH
- zvířata MeSH
- zygota cytologie MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
