Nucleostemin is a p53-interactive cell cycle progression factor that shuttles between the nucleolus and nucleoplasm, but it has no known involvement in ribosome synthesis. We found the dynamic properties of nucleostemin differed strikingly from fibrillarin (a protein directly involved in rRNA processing) both in response to rRNA transcription inhibition and in the schedule of reentry into daugh...

Dynamic changes in gene positioning contribute to differential expression of virulence-related gene families in protozoan pathogens; however, the role of nuclear architecture in gene expression in the human malaria parasite Plasmodium falciparum remains poorly understood. Here we investigated the developmentally regulated ribosomal RNA (rRNA) gene family in P. falciparum, which, unlike that in ...

for periods of 15 to 60 min resulted in disappearance of nucleolar DNA and diffusion of nucleolinar material, as demonstrated by toluidine blue-molybdate, acid phosphatase, and lead staining throughout the nucleolus. Ultrastructural studies of the heated cells indicated that the fibrillar component of the nucleolus, like the nucleolini, became diffusely distributed throughout the nucleolus and ...

Trypanosomatids possess two homologues of Nopp140: a canonical Nopp140 and a Nopp140-like protein (TbNoLP) in which a GAR domain replaces the C-terminal SRP40 domain. Both are phosphorylated and coimmunoprecipitate with RNA polymerase I. Each paralogue has a distinct subnuclear localization, and depletion of TbNoLP produces an enlarged nucleolus in which TbNopp140-containing regions disperse. T...

The nuclear space is mostly occupied by chromosome territories and nuclear bodies. Although this organization of chromosomes affects gene function, relatively little is known about the role of nuclear bodies in the organization of chromosomal regions. The nucleolus is the best-studied subnuclear structure and forms around the rRNA repeat gene clusters on the acrocentric chromosomes. In addition...

Here we show that the TATA-binding protein (TBP) is localized in the nucleoplasm and in the nucleolus of mammalian cells, consistent with its known involvement in transcription by RNA polymerase I, II, and III. In the nucleolus of actively growing cells, TBP colocalizes with upstream binding factor (UBF) and RNA polymerase I at the sites of rRNA transcription. During mitosis, when rRNA synthesi...

Correlative data are presented here on the developmental history, dynamics, histochemistry, and fine structure of intranuclear rodlets in chicken sympathetic neurons from in vivo material and long-term organized tissue cultures. The rodlets consist of bundles of approximately 70 +/- 10 A proteinaceous filaments closely associated with approximately 0.4-0.8 micro spheroidal, granulofibrillar (gf...

The proportions of the 4 componente of nucleoli: namely, granular component, fibrillar component, vacuolar space and the fibrillar centre material, were calculated by electron microscopical stereological procedures for human diploid fibroblaate (strain MRC-5) under 6 different culture conditions. Ueing nucleolar volumee obtained by light microscopy of unsectioned cella, estimates of the volume ...

In all eukaryotic cells, the nucleolus is functionally and structurally linked to rRNA synthesis and ribosome biogenesis. This compartment contains as well factors involved in other cellular activities, but the functional interconnection between non-ribosomal activities and the nucleolus (structure and function) still remains an open question. Here, we report a novel mass spectrometry analysis ...

Nucleolus is the major structural domain of the cell nucleus, which in addition to proteins contains ribosomal RNA (rRNA) at different stages of maturation (or pre-rRNA). In mammals, the onset of mitosis is accompanied by the inhibition of rRNA synthesis, nucleolus disassembly, and the migration of pre-rRNA to the cytoplasm. However, the precise role of cytoplasmic pre-rRNA in mitosis remains u...