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PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1997-2-28
pubmed:databankReference
pubmed:abstractText
We have analyzed the organization of pre-rRNA processing by confocal microscopy in pea root cell nucleoli using a variety of probes for fluorescence in situ hybridization and immunofluorescence. Our results show that transcript processing within the nucleolus is spatially highly organized. Probes to the 5' external transcribed spacer (ETS) and first internal transcribed spacer (ITS1) showed that the excision of the ETS occurred in a sub-region of the dense fibrillar component (DFC), whereas the excision of ITS1 occurred in the surrounding region, broadly corresponding to the granular component. In situ labelling with probes to the snoRNAs U3 and U14, and immunofluorescence labelling with antibodies to fibrillarin and SSB1 showed a high degree of coincidence with the ETS pattern, confirming that ETS cleavage and 18 S rRNA production occur in the DFC. ETS, U14, fibrillarin and SSB1 showed a fine substructure within the DFC comprising closely packed small foci, whereas U3 appeared more diffuse throughout the DFC. A third snoRNA, 7-2/MRP, was localised to the region surrounding the ETS, in agreement with its suggested role in ITS1 cleavage. All three snoRNAs were also frequently observed in numerous small foci in the nucleolar vacuoles, but none was detectable in coiled bodies. Antibodies to fibrillarin and SSB1 labelled coiled bodies strongly, though neither protein was detected in the nucleolar vacuoles. During mitosis, all the components analyzed, including pre-rRNA, were dispersed through the cell at metaphase, then became concentrated around the periphery of all the chromosomes at anaphase, before being localized to the developing nucleoli at late telophase. Pre-rRNA (ETS and ITS1 probes), U3 and U14 were also concentrated into small bodies, presumed to be pre-nucleolar bodies at anaphase.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9533
pubmed:author
pubmed:issnType
Print
pubmed:volume
109 ( Pt 6)
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1241-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
The organization of ribosomal RNA processing correlates with the distribution of nucleolar snRNAs.
pubmed:affiliation
Department of Cell Biology, John Innes Centre, Colney, Norwich, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't