scholarly journals Dynamic localization of RNase MRP RNA in the nucleolus observed by fluorescent RNA cytochemistry in living cells.

1995 ◽  
Vol 131 (6) ◽  
pp. 1649-1658 ◽  
Author(s):  
M R Jacobson ◽  
L G Cao ◽  
Y L Wang ◽  
T Pederson
Keyword(s):  
Rat Kidney ◽  
Living Cells ◽  
Dense Fibrillar Component ◽  
Optical Sectioning ◽  
Sequence Element ◽  
Dynamic Localization ◽  
Rnase Mrp ◽  
Stereo Reconstruction ◽  
Normal Rat ◽  
Fibrillar Component

The dynamic intra-nuclear localization of MRP RNA, the RNA component of the ribonucleoprotein enzyme RNase MRP, was examined in living cells by the method of fluorescent RNA cytochemistry (Wang, J., L.-G. Cao, Y.-L. Wang, and T. Pederson. 1991. Proc. Natl. Acad. Sci. USA. 88:7391-7395). MRP RNA very rapidly accumulated in nucleoli after nuclear microinjection of normal rat kidney (NRK) epithelial cells. Localization was specifically in the dense fibrillar component of the nucleolus, as revealed by immunocytochemistry with a monoclonal antibody against fibrillarin, a known dense fibrillar component protein, as well as by digital optical sectioning microscopy and 3-D stereo reconstruction. When MRP RNA was injected into the cytoplasm it was not imported into the nucleus. Nuclear microinjection of mutant MRP RNAs revealed that nucleolar localization requires a sequence element (nucleotides 23-62) previously implicated as a binding site for a nucleolar protein, the To antigen. These results demonstrate the dynamic localization of MRP RNA in the nucleus and provide important insights into the nucleolar targeting of MRP RNA.

scholarly journals Translocation and clustering of endosomes and lysosomes depends on microtubules.

1987 ◽  
Vol 105 (3) ◽  
pp. 1253-1265 ◽  
Author(s):  
R Matteoni ◽  
T E Kreis
Keyword(s):  
Rat Kidney ◽  
Living Cells ◽  
Cytochalasin D ◽  
Microtubule Organizing Center ◽  
Enhanced Fluorescence ◽  
Organelle Movement ◽  
Organizing Center ◽  
Normal Rat ◽  
Immunofluorescence Labeling

Indirect immunofluorescence labeling of normal rat kidney (NRK) cells with antibodies recognizing a lysosomal glycoprotein (LGP 120; Lewis, V., S.A. Green, M. Marsh, P. Vihko, A. Helenius, and I. Mellman, 1985, J. Cell Biol., 100:1839-1847) reveals that lysosomes accumulate in the region around the microtubule-organizing center (MTOC). This clustering of lysosomes depends on microtubules. When the interphase microtubules are depolymerized by treatment of the cells with nocodazole or during mitosis, the lysosomes disperse throughout the cytoplasm. Lysosomes recluster rapidly (within 30-60 min) in the region of the centrosomes either upon removal of the drug, or, in telophase, when repolymerization of interphase microtubules has occurred. During this translocation process the lysosomes can be found aligned along centrosomal microtubules. Endosomes and lysosomes can be visualized by incubating living cells with acridine orange. We have analyzed the movement of these labeled endocytic organelles in vivo by video-enhanced fluorescence microscopy. Translocation of endosomes and lysosomes occurs along linear tracks (up to 10 microns long) by discontinuous saltations (with velocities of up to 2.5 microns/s). Organelles move bidirectionally with respect to the MTOC. This movement ceases when microtubules are depolymerized by treatment of the cells with nocodazole. After nocodazole washout and microtubule repolymerization, the translocation and reclustering of fluorescent organelles predominantly occurs in a unidirectional manner towards the area of the MTOC. Organelle movement remains unaffected when cells are treated with cytochalasin D, or when the collapse of intermediate filaments is induced by microinjected monoclonal antivimentin antibodies. It can be concluded that translocation of endosomes and lysosomes occurs along microtubules and is independent of the intermediate filament and microfilament networks.

scholarly journals Effects of hypertonic stress on transforming growth factor-β activity in normal rat kidney cells

1998 ◽  
Vol 53 (6) ◽  
pp. 1654-1660 ◽  
Author(s):  
Toshihiro Sugiura ◽  
Atsushi Yamauchi ◽  
Hiroshi Kitamura ◽  
Yasuko Matusoka ◽  
Masaru Horio ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Rat Kidney ◽  
Transforming Growth Factor Β ◽  
Kidney Cells ◽  
Hypertonic Stress ◽  
Normal Rat

scholarly journals Adhesion-dependent and Contractile Ring-independent Equatorial Furrowing during Cytokinesis in Mammalian Cells

2005 ◽  
Vol 16 (8) ◽  
pp. 3865-3872 ◽  
Author(s):  
Masamitsu Kanada ◽  
Akira Nagasaki ◽  
Taro Q.P. Uyeda
Keyword(s):  
Mammalian Cells ◽  
Rat Kidney ◽  
Myosin Ii ◽  
Rho Kinase ◽  
Cellular Slime Mold ◽  
Animal Cells ◽  
Contractile Ring ◽  
Normal Rat ◽  
Cellular Slime ◽  
Coated Surfaces

Myosin II-dependent contraction of the contractile ring drives equatorial furrowing during cytokinesis in animal cells. Nonetheless, myosin II-null cells of the cellular slime mold Dictyostelium divide efficiently when adhering to substrates by making use of polar traction forces. Here, we show that in the presence of 30 μM blebbistatin, a potent myosin II inhibitor, normal rat kidney (NRK) cells adhering to fibronectin-coated surfaces formed equatorial furrows and divided in a manner strikingly similar to myosin II-null Dictyostelium cells. Such blebbistatin-resistant cytokinesis was absent in partially detached NRK cells and was disrupted in adherent cells if the advance of their polar lamellipodia was disturbed by neighboring cells. Y-27632 (40 μM), which inhibits Rho-kinase, was similar to 30 μM blebbistatin in that it inhibited cytokinesis of partially detached NRK cells but only prolonged furrow ingression in attached cells. In the presence of 100 μM blebbistatin, most NRK cells that initiated anaphase formed tight furrows, although scission never occurred. Adherent HT1080 fibrosarcoma cells also formed equatorial furrows efficiently in the presence of 100 μM blebbistatin. These results provide direct evidence for adhesion-dependent, contractile ring-independent equatorial furrowing in mammalian cells and demonstrate the importance of substrate adhesion for cytokinesis.

scholarly journals DNA microarray analysis of normal rat kidney epithelial cells treated with cadmium

2011 ◽  
Vol 36 (1) ◽  
pp. 127-129 ◽  
Author(s):  
Maki Tokumoto ◽  
Tomoaki Ohtsu ◽  
Akiko Honda ◽  
Yasuyuki Fujiwara ◽  
Hisamitsu Nagase ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Microarray Analysis ◽  
Dna Microarray ◽  
Rat Kidney ◽  
Dna Microarray Analysis ◽  
Normal Rat ◽  
Kidney Epithelial Cells

A study on nucleolar DNA: isolation of DNA from fibrillar components and ultrastructural localization of different DNA probes

1993 ◽  
Vol 104 (4) ◽  
pp. 1199-1205 ◽  
Author(s):  
P. Hozak ◽  
C. Schofer ◽  
J. Sylvester ◽  
F. Wachtler
Keyword(s):  
Ribosomal Rna ◽  
Sertoli Cells ◽  
Ultrastructural Localization ◽  
Ribosomal Rna Genes ◽  
Border Region ◽  
Dense Fibrillar Component ◽  
Mitotic Chromosomes ◽  
Electron Microscopic ◽  
Fibrillar Component ◽  
Rna Genes

The nature and localization of DNA contained in the fibrillar centres and the dense fibrillar component (the fibrillar complex) in the nucleoli, was studied in human LEP cells, Sertoli cells, spermatogonia A and in mitotic chromosomes of stimulated lymphocytes. A novel procedure for isolating the intact fibrillar complex from LEP cells was used; the complex contains DNA that hybridizes to secondary constrictions of mitotic chromosomes and to 28 S rDNA sequences, on Southern blots. Electron microscopic DNA-DNA in situ hybridization was performed, with (a) a probe prepared from DNA extracted from the fibrillar complex of LEP cells, (b) a probe for human total genomic DNA, and (c) a probe for the transcribed part of human rDNA. On the basis of the results obtained we conclude that the ribosomal RNA genes in human Sertoli cells and spermatogonia A are predominantly associated with the dense fibrillar component, including the border region between fibrillar centres and the dense fibrillar component. The ribosomal RNA genes are the main, if not exclusive, DNA type present in the fibrillar complex in the studied cell types.

scholarly journals Localization of DNA in the fibrillar components of the nucleolus: a cytochemical and morphometric study.

1993 ◽  
Vol 41 (6) ◽  
pp. 829-836 ◽  
Author(s):  
M Derenzini ◽  
F Farabegoli ◽  
D Trerè
Keyword(s):  
Morphometric Analysis ◽  
Mean Value ◽  
Morphometric Study ◽  
Dense Fibrillar Component ◽  
Thin Sections ◽  
Fibrillar Center ◽  
The Mean ◽  
Fibrillar Component ◽  
Resting Lymphocytes ◽  
The Relationship

We studied the distribution of DNA in human circulating lymphocyte nucleoli using three different cytochemical methods for selective visualization of DNA in thin sections: the Feulgen-like osmium-ammine reaction, the NAMA-Ur procedure, and the osmium-ammine staining in glycine buffer, pH 1.5. All three methods indicated the presence of uniformly distributed, highly decondensed DNA filaments forming a large solitary agglomerate in the central part of the nucleolar area, corresponding to the solitary large fibrillar center (FC) as revealed by uranium and lead staining. We also studied the relationship between DNA agglomerates and nucleolar fibrillar components in resting and phytohemagglutinin (PHA)-stimulated lymphocytes by morphometric analysis of the areas occupied by these structures. In resting lymphocytes the mean area of the DNA agglomerates was 0.479 micron 2 +/- 0.161 SD, whereas that of FCs was 0.380 micron 2 +/- 0.149 SD, with a ratio of 1.26. In PHA-stimulated lymphocytes the mean area of the DNA agglomerates was 0.116 micron 2 +/- 0.056 SD, whereas that of the FCs was 0.075 micron 2 +/- 0.032 SD, with a ratio of 1.55. In PHA-stimulated lymphocytes we also measured the area occupied by the FCs plus the closely associated dense fibrillar component (DFC). The mean value of these two fibrillar components was 0.206 micron 2 +/- 0.081 SD. These data demonstrate that decondensed DNA filaments are uniformly distributed in the FCs and that in transcriptionally active nucleoli they are also present in the proximal portion of the DFC surrounding the FCs.

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