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Summary Nucleolus-associated bodies (NABs) occur in interphase nuclei of many plant species. The present work shows that, inZea mays, NABs are present in dry seeds as well as in germinating tissues. The frequency of these nuclear bodies remains more or less constant during the first 24 h of imbibition but decreases significantly during the next 24 h. By the time the nucleolus reaches maturation and contains granular zones, these bodies are still found in close association with the surface of this organelle, as is the case in mature root meristematic cells. Immunocytochemical observations on both dry seeds and germinating tissues further revealed that NABs reacted positively with a monoclonal antibody (mAbK121) recognizing the m3G cap of sn(small nuclear)RNAs. It is, therefore, concluded that the NABs present in such tissues already contain components characterizing snRNPs (small nuclear ribonucleoproteins) in mature tissues. The possible function of NABs as storage deposits of snRNPs in dry seeds and early germinating tissues is discussed. In view of their many similarities with the coiled bodies described in both animal and plant cells, it is most likely that NABs correspond to those structures.Abbreviations BSA
bovine serum albumin
- DABCO
1,4-diazabicyclo (2.2.2)octane
- EDTA
ethylenediaminetetraacetic acid
- IgM
immunoglobulin M
- NAB
nucleolus-associated body
- AO
acridine orange
- NAC
nucleolus-associated chromatin
- PBS
phosphate-buffered saline
- snRNA
small nuclear ribonucleic acid
- snRNP
small nuclear ribonucleoprotein 相似文献
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Gabillard JC Ulisse S Baldini E Sorrenti S Cremet JY Coccaro C Prigent C D'Armiento M Arlot-Bonnemains Y 《Biochemical and biophysical research communications》2011,(4):647-653
Aurora-C, a member of the Aurora kinase family, is implicated in the regulation of mitosis. In contrast to Aurora-A and Aurora-B its cellular localization and functions are poorly characterized. TACC1 protein belongs to the transforming acidic coiled-coil family shown to interact with the Aurora kinases. In the present study we analyzed the interaction between Aurora-C and TACC1 by means of immunofluorescence (IF), co-immunoprecipitation (IP) and in vitro phosphorylation experiments. We demonstrated that Aurora-C and TACC1 proteins co-localize to the midbody of HeLa cells during cytokinesis. Immunoprecipitated TACC1 from HeLa cell extracts was associated with Aurora-C. In addition, the interaction of the two proteins was tested by analyzing the phosphorylation of TACC1 in vitro. The results demonstrated that TACC1 is phosphorylated by Aurora-C on a serine at position 228. In conclusion, the study demonstrated that TACC1 localizes at the midbody during cytokinesis and interacts with and is a substrate of Aurora-C, which warrant further investigation in order to elucidate the functional significance of this interaction. 相似文献
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Stanley G. Harris Terence E. Martin Harold C. Smith 《Molecular and cellular biochemistry》1988,84(1):17-28
The organization of select proteins within ribonucleoprotein particles containing heterogeneous nuclear and uridine-rich small nuclear RNAs (hnRNP and UsnRNP respectively) was examined by chemical cross-linking and ribonuclease digestion using diagonal two dimensional PAGE and immunoblotting detection systems. Monoclonal antibodies specific for A2, C1 and C2 hnRNP proteins, detected these proteins at gel coordinates which suggested homotypic dimers and trimers of A2 and homotypic trimers, hexamers and larger multimers of C1 and C2. Ribonuclease digestion did not alter the cross-linking properties of hnRNP C1 and C2 proteins but did result in loss of A2 homotypic dimers and trimers. Blots simultaneously reacted with hnRNP specific monoclonal antibodies and autoimmune patient serum (RNP/Sm), or monoclonal antibodies reactive with the U1 hnRNP specific 63 kDa protein and/or the UsnRNP common proteins B, B and D revealed no complexes which would indicate interactions between hnRNPs and UsnRNPs. The U1 UsnRNP specific 63 kDa protein appeared not to be cross-linked to UsnRNP common B,B and D proteins. The data also suggested that UsnRNP common protein D was cross-linkable to UsnRNP common proteins D, E and G but not to B and B. The cross-linking properties of D were unaffected by ribonuclease digestion. In contrast, ribonuclease digestion resulted in an inability to cross-link select complexes containing either B and B, or p63. The data suggest that both hnRNPs and UsnRNPs are comprised of RNA-dependent and RNA-independent protein-protein interactions.Abbreviations RNP
Ribonucleoprotein particle
- UsnRNP
RNP containing uridine rich small nuclear RNA
- hnRNP
RNP containing heterogeneous nuclear RNA
- PMSF
Phenylmethylsulfonyl Fluoride
- TEO
Triethanolamine
- EDTA
Ethylenediaminetetra Acetic Acid
- DTT
Dithiothreitol
- NEM
N-Ethylmaleimide
- DTBP
Dimethyl 3,3-Dithiobis Propionimidate
- ITH
2-Iminothiolane
- SDS
Sodium Dodecyl Sulfate
- PAGE
Polyacrylamide Gel Electrophoresis
- SLE
Systemic Lupus Erythematosus 相似文献
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Gerardo Vazquez-Nin Alma Ortiz Aurora Lopez Olga Echeverria 《Biology of the cell / under the auspices of the European Cell Biology Organization》1989,65(2):133-138
Nuclear ribonucleoprotein particles were studied in the central nervous system of the rat after fixation by perfusion with hypotonic-detergent formaldehyde. Beads-on-a-string structures (polyparticles or chains) formed of 14-nm granules related by a 7-nm thick filament were found. These polyparticles are positively contrasted by a preferential method for ribonucleoproteins and they are sensitive to RNase. Perichromatin granules are loosened by this fixation and their internal structure is clearly depicted. They are composed of a tangled mass of 3-nm thick filaments, but lack 14-nm granules. The internal filaments of the perichromatin granules display frequent continuities with polyparticles. These results show that polyparticles correspond to perichromatin fibrils visualized in nuclei by standard fixation procedures. 相似文献
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The recently developed method of sucrose gradient electrophoresis has been used in the investigation of mRNA containing particles prepared in an undenatured state. The particles containing messenger RNA migrate as a homogeneous fraction with a mobility different from that of ribosomal praticles. Informosomes and polysomal mRNPs have about the same mobility. On the contrary artificial complexes, formed by the reaction of cytoplasmic binding factor with RNA, migrate as a heterogeneous fraction. The particles carrying mRNA are drastically and irreversibly affected by a treatment with EDTA. Sodium deoxycholate removes some proteins but seems also to denature them. After treatment by high salt or Sodium deoxycholate the mRNPs migrate as a homogeneous fraction showing that all particles are equally affected. 相似文献