Biomaterial Database

Immunoelectron microscopic localization of snRNPs. 1983

D L Spector, and W H Schrier, and H Busch

Small nuclear ribonucleoprotein particles (snRNPs) were identified in nuclear sonicates of Novikoff hepatoma ascites cells and in intact Novikoff hepatoma and PtK2 cells by immunofluorescence and immunoelectron microscopy. Auto-antibodies (anti-Sm and anti-RNP) obtained from patients with systemic lupus erythematosus an autoimmune disease, were used to localize snRNP particles. The Sm antibody is specific for U1, U2, U4, U5 and U6 containing snRNPs. The RNP antibody is specific for only U1 containing snRNPs. Isolated particles, 120 +/- 10 A in diameter, were found to be associated with ferritin-conjugated goat anti-human antibodies coupled to Sm antibodies. In addition, these particles (snRNPs) were occasionally associated with larger particles measuring 230 +/- 10 A in diameter which are presumed to be hnRNP particles. Double label immunofluorescence and immunoelectron microscopy have shown Sm and RNP antibodies to colocalize in PtK2 cells. However, the perinucleolar chromatin and juxtanuclear envelope chromatin was devoid of RNP immunostaining. Therefore, U1 containing snRNPs do not appear to be in these regions. The Sm antibody localizes in a nuclear network including the perinucleolar chromatin and juxtanuclear envelope chromatin. Cells treated with the drug DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole), which inhibits hnRNA synthesis, show an altered pattern of Sm immunostaining. Such cells contain large clusters of snRNPs which do not extend to the perinucleolar chromatin or perinuclear lamina chromatin. Nuclear matrix preparations maintain an snRNP nuclear network as visualized by Sm immunofluorescence. It is notable that the size and density of the immunostained particles in the nuclear network during interphase, is similar to that of interchromatinic granules.

UI	MeSH Term	Description	Entries
D007614	Macropodidae	A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos.	Kangaroos,Macropus,Petrogale,Quokkas,Setonix,Wallabies,Wallabies, Rock,Wallaroo,Macropus robustus,Kangaroo,Petrogales,Quokka,Rock Wallabies,Rock Wallaby,Wallaby,Wallaby, Rock,Wallaroos
D008114	Liver Neoplasms, Experimental	Experimentally induced tumors of the LIVER.	Hepatoma, Experimental,Hepatoma, Morris,Hepatoma, Novikoff,Experimental Hepatoma,Experimental Hepatomas,Experimental Liver Neoplasms,Hepatomas, Experimental,Neoplasms, Experimental Liver,Experimental Liver Neoplasm,Liver Neoplasm, Experimental,Morris Hepatoma,Novikoff Hepatoma
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002466	Cell Nucleolus	Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)	Plasmosome,Cell Nucleoli,Nucleoli, Cell,Nucleolus, Cell,Plasmosomes
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D002843	Chromatin	The material of CHROMOSOMES. It is a complex of DNA; HISTONES; and nonhistone proteins (CHROMOSOMAL PROTEINS, NON-HISTONE) found within the nucleus of a cell.	Chromatins
D003593	Cytoplasm	The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)	Protoplasm,Cytoplasms,Protoplasms
D005293	Ferritins	Iron-containing proteins that are widely distributed in animals, plants, and microorganisms. Their major function is to store IRON in a nontoxic bioavailable form. Each ferritin molecule consists of ferric iron in a hollow protein shell (APOFERRITINS) made of 24 subunits of various sequences depending on the species and tissue types.	Basic Isoferritin,Ferritin,Isoferritin,Isoferritin, Basic