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Nucleolus

About: Nucleolus is a research topic. Over the lifetime, 5873 publications have been published within this topic receiving 232435 citations. The topic is also known as: GO:0005730 & cell nucleolus.


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Journal ArticleDOI
TL;DR: Results indicated that Mi-2β and RFP, known to be involved in transcriptional repression in the nucleus, co-localize with MCRS1 in the nucleolus and appear to activate the rRNA transcription.

71 citations

Journal Article
TL;DR: It is suggested that pol I, pol II, and pol III transcription and processing complexes are preassembled in the CBs before transport to the sites of transcription on the chromosomes and in the nucleoli.
Abstract: Cajal bodies (CBs) are small nuclear organelles that contain the three eukaryotic RNA polymerases and variety of factors involved in transcription and processing of all types of RNA. A number of these factors, as well as subunits of polymerase (pol) II itself, are rapidly and specifically targeted to CBs when injected into the cell. It is suggested that pol I, pol II and pol III transcription and processing complexes are preassembled in the CBs before transport to the sites of transcription on the chromosomes and in the nucleoli.

70 citations

Journal ArticleDOI
TL;DR: This report purified the hsp40 in HeLa cells, using modified two-dimensional gel electrophoresis, and determined the amino terminal amino acid sequence of this protein, which is homologous to DNAJ, an Escherichia coli heat-shock protein, as well as to DnaJ-homologous proteins in yeast.
Abstract: We earlier discovered a novel 40-kDa protein (hsp40) induced by heat shock and other stresses in mammalian and avian cells. In this report, we purified the hsp40 in HeLa cells, using modified two-dimensional gel electrophoresis, and determined the amino terminal amino acid sequence of this protein. The hsp40 is homologous to DnaJ, an Escherichia coli heat-shock protein, as well as to DnaJ-homologous proteins in yeast such as SCJ1, Sec63/Np11, YDJ1 and SIS1. Indirect immunofluorescence staining using an anti-hsp40 polyclonal antibody demonstrated that hsp40 was localized faintly throughout the cell in non-heat-shocked cells and was accumulated in nuclei and nucleoli in heat-shocked cells. The intracellular localization of hsp40 was very similar to that of hsp70, suggesting that these two hsps colocalize in heat-shocked HeLa cells.

70 citations

Journal ArticleDOI
TL;DR: These results demonstrate that nucleolar components involved in pre-rRNA processing, including rRNA itself, probably in an incompletely processed form, are transferred from the parental to the daughter cell nucleoli by means of transient structures, such as the perichromosomal sheath and prenucleolar bodies.

70 citations

Journal ArticleDOI
TL;DR: It is suggested that nucleoli show at least two basic reaction patterns to inhibitors of RNA synthesis, one typified by actinomycin D and one by ethionine.
Abstract: The structure of nuclei and nucleoli of hepatic cells after short-term ethionine administration was investigated with the electron microscope. By 1½ hr after the injection, a distinct alteration occurred in the nucleoli which was characterized by the appearance of electron-opaque masses in the nucleolonema. After 6–8 hr, the nucleoli showed partial fragmentation into small, dense masses. Large aggregates of interchromatinic granules appeared in the nucleoplasm. Condensation of chromatin became prominent in the nucleoplasm particularly along the nuclear membrane. By 12 hr almost complete fragmentation of nucleoli had occurred. The administration of adenine or methionine at 4 hr prevented the development of nucleolar changes. Also, adenine administration at 8 hr after ethionine completely reversed the nucleolar lesion by 12 hr. After methionine administration at 8 hr, many nucleoli showed incomplete reconstruction with many twisted ropelike structures when viewed 4 hr later. Identical structures were found when adenine was given at 8 hr, and animals were sacrificed 2 hr later. On the basis of this observation, the simplified structures of nucleoli found 2 hr after adenine or 4 hr after methionine appeared to be precursors of the nucleolonema. It is suggested that nucleoli show at least two basic reaction patterns to inhibitors of RNA synthesis, one typified by actinomycin D and one by ethionine.

70 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023145
2022209
2021143
2020125
2019139
2018121