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A class of nonribosomal nucleolar components is located in chromosome periphery and in nucleolus-derived foci during anaphase and telophase 总被引:9,自引:0,他引:9
Miroslav Dundr U. Thomas Meier Nancy Lewis David Rekosh Marie-Louise Hammarskjöld Mark O. J. Olson 《Chromosoma》1997,105(7-8):407-417
The subcellular location of several nonribosomal nucleolar proteins was examined at various stages of mitosis in synchronized
mammalian cell lines including HeLa, 3T3, COS-7 and HIV-1 Rev-expressing CMT3 cells. Nucleolar proteins B23, fibrillarin,
nucleolin and p52 as well as U3 snoRNA were located partially in the peripheral regions of chromosomes from prometaphase to
early telophase. However, these proteins were also found in large cytoplasmic particles, 1–2 μm in diameter, termed nucleolus-derived
foci (NDF). The NDF reached maximum numbers (as many as 100 per cell) during mid- to late anaphase, after which their number
declined to a few or none during late telophase. The decline in the number of NDF approximately coincided with the appearance
of prenucleolar bodies and reforming nucleoli. The HIV-1 Rev protein and a mutant Rev protein defective in its nuclear export
signal were also found in the NDF. The mutant Rev protein precisely followed the pattern of localization of the above nucleolar
proteins, whereas the wild-type Rev did not enter nuclei until G1 phase. The nucleolar shuttling phosphoprotein Nopp 140 did
not follow the above pattern of localization during mitosis: it dispersed in the cytoplasm from prometaphase through early
telophase and was not found in the NDF. Although the NDF and mitotic coiled bodies disappeared from the cytoplasm at approximately
the same time during mitosis, protein B23 was not found in mitotic coiled bodies, nor was p80 coilin present in the NDF. These
results suggest that a class of proteins involved in preribosomal RNA processing associate with chromosome periphery and with
NDF as part of a system to conserve and deliver preexisting components to reforming nucleoli during mitosis.
Edited by: S. A. Gerbi 相似文献
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Ribosomal gene reiteration in a marsupial species with an X-linked nucleolar organizer 总被引:1,自引:0,他引:1
The number of ribosomal cistrons in somatic cells of males and females of Macropus eugenii have been estimated using RNA/DNA hybridization in 70% (v/v) formamide. The male has one X-linked active nucleolar organizer and the female two and while the number of ribosomal cistrons is variable between the four males examined (31-65 copies), it is substantially less than the number present in the three females (94-103 copies). There is, therefore, no evidence of dosage compensation by amplification. 相似文献
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C López-Iglesias J L Arias 《Biology of the cell / under the auspices of the European Cell Biology Organization》1987,60(1):9-14
Quantitative changes in the size of pinealocyte nucleoli have been reported in various studies on this cell type. However, the significance of quantitative changes in the nucleolar components is unknown. The present study is an attempt to analyze ultrastructural and morphometric modifications occurring in the pinealocyte nucleolar components during the estrous cycle in female rats. The fibrillar centers showed an increase during estrus consistent with a decrease in pinealocyte nucleolar activity and melatonin pineal levels. The fibrillar components and granular components tended to display a reciprocal relationship. An increase in the dense fibrillar component took place at metaestrus and diestrus when melatonin synthesis increased in pinealocytes. Maximum values of granular and interstitial components were found at the proestrus phase before the day of ovulation. 相似文献
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Gazda HT Grabowska A Merida-Long LB Latawiec E Schneider HE Lipton JM Vlachos A Atsidaftos E Ball SE Orfali KA Niewiadomska E Da Costa L Tchernia G Niemeyer C Meerpohl JJ Stahl J Schratt G Glader B Backer K Wong C Nathan DG Beggs AH Sieff CA 《American journal of human genetics》2006,79(6):1110-1118
Diamond-Blackfan anemia (DBA) is a rare congenital red-cell aplasia characterized by anemia, bone-marrow erythroblastopenia, and congenital anomalies and is associated with heterozygous mutations in the ribosomal protein (RP) S19 gene (RPS19) in approximately 25% of probands. We report identification of de novo nonsense and splice-site mutations in another RP, RPS24 (encoded by RPS24 [10q22-q23]) in approximately 2% of RPS19 mutation-negative probands. This finding strongly suggests that DBA is a disorder of ribosome synthesis and that mutations in other RP or associated genes that lead to disrupted ribosomal biogenesis and/or function may also cause DBA. 相似文献
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mTOR-dependent regulation of ribosomal gene transcription requires S6K1 and is mediated by phosphorylation of the carboxy-terminal activation domain of the nucleolar transcription factor UBF 总被引:2,自引:0,他引:2 下载免费PDF全文
Hannan KM Brandenburger Y Jenkins A Sharkey K Cavanaugh A Rothblum L Moss T Poortinga G McArthur GA Pearson RB Hannan RD 《Molecular and cellular biology》2003,23(23):8862-8877
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Ameeta K. Agarwal · Susan N. Parrish · D. D. Blumberg 《Differentiation; research in biological diversity》1999,65(2):73-88
Starvation for amino acids initiates the developmental cycle in the cellular slime mold, Dictyostelium discoideum. Upon starvation one of the earliest developmental events is the selective loss of the ribosomal protein mRNAs from polysomes. This loss depends upon sequences in the 5' non-translated leader of the ribosomal protein (r-protein) mRNAs. Here evidence is presented which indicates that those cells which will become prestalk cells express the ribosomal protein genes during development under starvation conditions. Cells which enter the prespore pathway shut off r-protein synthesis. The promoter and 5' non-translated leader sequences from two ribosomal protein genes, the rp-L11 and the rp-S9 genes, are fused to the Escherichia coli beta-galactosidase reporter gene. While beta-galactosidase enzyme activity is detected in situ in most growing cells, by 15 h of development beta-galactosidase enzyme activity is largely lost from the prespore cells although strong beta-galactosidase enzyme activity is present in the prestalk cells. These observations suggest the possibility that the ribosomal protein mRNAs are excluded from polysomes in a cell-type-specific manner. 相似文献
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Growth temperature modifies the cycle time in Allium cepa L. root meristems, affecting neither the cell size nor the relative duration of the cycle phases. It was to be expected that a similar nucleolus would be found whose activity was merely modified by temperature as any other enzymatic reaction. However, stereology of nucleoli growing at two physiological temperatures (10 and 25 °C) showed that both the fibrillar and granular components were 1.3 and 2 times respectively more abundant at the lower temperature. These nucleoli had also twice as many active nucleolar RNA polymerases as shown after the in situ assay. 相似文献