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Dynamic relocation of transcription and splicing factors dependent upon transcriptional activity
Author(s) -
Zeng Changqing,
Kim Euikyung,
Warren Stephen L.,
Berget Susan M.
Publication year - 1997
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/16.6.1401
Subject(s) - biology , rna splicing , relocation , transcription factor , transcription (linguistics) , genetics , alternative splicing , computational biology , microbiology and biotechnology , evolutionary biology , gene , messenger rna , rna , linguistics , philosophy , computer science , programming language
Recent interest in understanding the spatial organization of gene expression has focused attention on nuclear structures known as speckles or interchromatin granule clusters (IGCs) revealed by immunofluorescence or electron microscopy. Staining of nuclear factors involved in pre‐mRNA splicing or, more recently, transcription, reveals 20–40 speckles per nucleus, resulting in the intriguing suggestion that speckles are nuclear sites of transcription and processing. In contrast, other investigations have observed transcription in other areas of the nucleus. In this study, we have examined the localization of active transcription as detected by uridine incorporation and recently developed RNA polymerase II antibodies, and compared this pattern with that of known splicing and polyadenylation factors. Our results indicate that in actively transcribing cells, transcription and splicing factors are dispersed throughout the nucleus with abundant sites of preferred localization. In contrast, in poorly transcribing cells, polymerase II and splicing factors localize to speckles. In nuclei inactivated for transcription by drugs or heat shock, the speckle type of co‐localization is accentuated. These observations suggest that bulk transcription and splicing occur throughout the nucleus during periods of active transcription; and that factors involved in these two processes re‐locate to minimal speckle domains during periods of inactive transcription.