Hypophosphorylated SR splicing factors transiently localize around active nucleolar organizing regions in telophase daughter nuclei

Bubulya, P. A., Prasanth, K. V. , Deerinck, T. J., Gerlich, D., Beaudouin, J., Ellisman, M. H. , Ellenberg, J., Spector, D. L. (October 2004) Hypophosphorylated SR splicing factors transiently localize around active nucleolar organizing regions in telophase daughter nuclei. J Cell Biol, 167 (1). pp. 51-63. ISSN 0021-9525 (Print)

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URL: http://www.ncbi.nlm.nih.gov/pubmed/15479736
DOI: 10.1083/jcb.200404120


Upon completion of mitosis, daughter nuclei assemble all of the organelles necessary for the implementation of nuclear functions. We found that upon entry into daughter nuclei, snRNPs and SR proteins do not immediately colocalize in nuclear speckles. SR proteins accumulated in patches around active nucleolar organizing regions (NORs) that we refer to as NOR-associated patches (NAPs), whereas snRNPs were enriched at other nuclear regions. NAPs formed transiently, persisting for 15-20 min before dissipating as nuclear speckles began to form in G1. In the absence of RNA polymerase II transcription, NAPs increased in size and persisted for at least 2 h, with delayed localization of SR proteins to nuclear speckles. In addition, SR proteins in NAPs are hypophosphorylated, and the SR protein kinase Clk/STY colocalizes with SR proteins in NAPs, suggesting that phosphorylation releases SR proteins from NAPs and their initial target is transcription sites. This work demonstrates a previously unrecognized role of NAPs in splicing factor trafficking and nuclear speckle biogenesis.

Item Type: Paper
Uncontrolled Keywords: Cell Nucleolus/ ultrastructure Cell Nucleus/enzymology/metabolism/ultrastructure DNA, Complementary/metabolism Hela Cells Humans Microscopy, Electron Microscopy, Fluorescence Nuclear Proteins/metabolism Nucleolus Organizer Region Phosphorylation RNA Polymerase II/metabolism RNA, Messenger/metabolism Ribonucleoproteins, Small Nuclear/metabolism Sarcoplasmic Reticulum/ metabolism Telophase Time Factors Transcription, Genetic Transfection
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > SR proteins
organs, tissues, organelles, cell types and functions > organelles, types and functions > mitosis
CSHL Authors:
Communities: CSHL labs > Spector lab
Depositing User: CSHL Librarian
Date: 11 October 2004
Date Deposited: 13 Feb 2012 17:53
Last Modified: 29 Jan 2015 14:57
PMCID: PMC2172523
Related URLs:
URI: https://repository.cshl.edu/id/eprint/22332

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