Document Detail


Abnormal integrity of the nucleolus associated with cell cycle arrest owing to the temperature-sensitive ubiquitin-activating enzyme E1.
MedLine Citation:
PMID:  7749560     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A mouse cell mutant, ts85, containing the temperature-sensitive ubiquitin-activating enzyme was arrested in G2 phase at the non-permissive temperature. In the arrested cells, azure C, a nucleolus-specific stain, revealed a U-shaped or ring-shaped arrangement of nucleolar lobes with an unstained region in the center. Silver staining of the nucleolar organizer region (NOR) and fluorescence in situ hybridization (FISH) with rDNA both gave signals in azure C-positive regions. Electron microscopic examination revealed a cloud of unidentified electron-dense particles (diameter approximately 70 nm) in the azure C-negative center space. When the arrested cells were released into M-phase, we observed the association of NOR-bearing chromosomes with a pulverization-like abnormality. FISH with rDNA and NOR silver staining demonstrated that the pulverization-like abnormality was restricted to NORs. The frequent occurrence of persistent nucleolar material in prophase and prometaphase of the stressed cells after release indicated a delayed dissociation of the nucleolus that brought about the abnormal chromosomes in M-phase. ts85 cells transfected with the mouse E1 cDNA recovered growth at the non-permissive temperature and no longer showed abnormal nucleolar morphology. It seems that the ubiquitin system plays a role in the dissolution of the nucleolus, possibly involving the NOR-bearing chromosomes.
Authors:
T Sudha; H Tsuji; M Sameshima; Y Matsuda; S Kaneda; Y Nagai; F Yamao; T Seno
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Chromosome research : an international journal on the molecular, supramolecular and evolutionary aspects of chromosome biology     Volume:  3     ISSN:  0967-3849     ISO Abbreviation:  Chromosome Res.     Publication Date:  1995 Mar 
Date Detail:
Created Date:  1995-06-20     Completed Date:  1995-06-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9313452     Medline TA:  Chromosome Res     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  115-23     Citation Subset:  IM    
Affiliation:
Down's Research Society, Madras, India.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Cycle / physiology*
Cell Division
Cell Nucleolus / physiology*,  ultrastructure
Chromosome Aberrations*
DNA, Ribosomal / isolation & purification
In Situ Hybridization, Fluorescence
Interphase
Ligases / genetics*
Mice
Microscopy, Electron
Mutation
Nucleolus Organizer Region / physiology*,  ultrastructure
Silver Staining
Tumor Cells, Cultured
Ubiquitin-Activating Enzymes
Ubiquitin-Protein Ligases
Ubiquitins / metabolism
Chemical
Reg. No./Substance:
0/DNA, Ribosomal; 0/Ubiquitins; EC 6.-/Ligases; EC 6.3.2.19/Ubiquitin-Activating Enzymes; EC 6.3.2.19/Ubiquitin-Protein Ligases

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