Abstract:
:In plant cells nucleolar fibrillar centres (FCs) undergo ultrastructural changes, depending on the nucleolar activity. We have found two types of FC structure in nucleoli with either high or low activity, to which we have given the conventional names of homogeneous and heterogeneous, respectively. The first type is characterized by the presence of fibres that we describe structurally and cytochemically as decondensed chromatin; the second type, in addition to these fibres, contains a variable number of dense cores made up of condensed chromatin. Moreover, RNA does not appear to be present in FCs, while proteins are a major component. Autoradiography after tritiated uridine incorporation shows that FCs are not the site of transcription, but that this takes place in the fibrillar component; the same result is obtained using the lead acetate fixation technique for detecting orthophosphate ions. This fact leads us to think that FCs are not the whole interphasic counterpart of the mitotic nucleolar organizing region (NOR), as stated by other authors, but only the portion of the NOR that is temporarily inactive in transcription; the transcriptionally active part of the NOR is in the fibrillar component, bound to its earliest product of transcription. Thus, FCs and the fibrillar component constitute a functional unit.
journal_name
J Cell Scijournal_title
Journal of cell scienceauthors
Risueño MC,Medina FJ,Moreno Díaz de la Espina Ssubject
Has Abstractpub_date
1982-12-01 00:00:00pages
313-29eissn
0021-9533issn
1477-9137journal_volume
58pub_type
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journal_title:Journal of cell science
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journal_title:Journal of cell science
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journal_title:Journal of cell science
pub_type: 杂志文章,评审
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更新日期:1997-06-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
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更新日期:2001-05-01 00:00:00
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journal_title:Journal of cell science
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更新日期:1990-10-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:
更新日期:1994-04-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:
更新日期:1987-11-01 00:00:00
abstract::Mammalian Staufen2 (Stau2) is involved in mRNA transport in neurons. Here, we report that Stau2 is a double-stranded RNA-binding protein that is mainly expressed in the brain. We show that Stau2 is found in the somatodendritic compartment of neurons. In dendrites, Stau2 is aligned on individual tracts and colocalizes ...
journal_title:Journal of cell science
pub_type: 杂志文章
doi:
更新日期:2002-08-15 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
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更新日期:2003-10-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
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更新日期:2017-04-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:10.1242/jcs.031641
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journal_title:Journal of cell science
pub_type: 杂志文章
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更新日期:1992-12-01 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:10.1242/jcs.031922
更新日期:2008-08-15 00:00:00
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:
更新日期:1992-09-01 00:00:00
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journal_title:Journal of cell science
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journal_title:Journal of cell science
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journal_title:Journal of cell science
pub_type: 杂志文章
doi:
更新日期:1981-12-01 00:00:00
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journal_title:Journal of cell science
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journal_title:Journal of cell science
pub_type: 杂志文章,评审
doi:
更新日期:2000-01-01 00:00:00
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