title: Periodic expression of Sm proteins parallels formation of nuclear Cajal bodies and cytoplasmic snRNP-rich bodies.
abstract: Small nuclear ribonucleoproteins (snRNPs) play a fundamental role in pre-mRNA processing in the nucleus. The biogenesis of snRNPs involves a sequence of events that occurs in both the nucleus and cytoplasm. Despite the wealth of biochemical information about the cytoplasmic assembly of snRNPs, little is known about the spatial organization of snRNPs in the cytoplasm. In the cytoplasm of larch microsporocytes, a cyclic appearance of bodies containing small nuclear RNA (snRNA) and Sm proteins was observed during anther meiosis. We observed a correlation between the occurrence of cytoplasmic snRNP bodies, the levels of Sm proteins, and the dynamic formation of Cajal bodies. Larch microsporocytes were used for these studies. This model is characterized by natural fluctuations in the level of RNA metabolism, in which periods of high transcriptional activity are separated from periods of low transcriptional activity. In designing experiments, the authors considered the differences between the nuclear and cytoplasmic phases of snRNP maturation and generated a hypothesis about the direct participation of Sm proteins in a molecular switch triggering the formation of Cajal bodies.
authors: Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Toruń, Poland. darsmol@umk.pl
authors: Dariusz J
authors: DJ
authors: Smoliński
authors: Bogdan
authors: B
authors: Wróbel
authors: Anna
authors: A
authors: Noble
authors: Agnieszka
authors: A
authors: Zienkiewicz
authors: Alicja
authors: A
authors: Górska-Brylass
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D020541:Coiled Bodies / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D035264:Flowers / Q000378:metabolism; D028221:Larix / Q000166:cytology* / Q000502:physiology; D008540:Meiosis / Q000502:physiology; D010507:Periodicity; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000378:metabolism; D011058:Pollen / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism*; D055532:SMN Complex Proteins / Q000378:metabolism*; D013573:Synaptonemal Complex / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D017411:Ribonucleoproteins, Small Nuclear; D055532:SMN Complex Proteins