Transcription-dependent rearrangements of actin and nuclear myosin i in the nucleolus

V. V. Philimonenko, J. Janáček, M. Harata, P. Hozák

    Research output: Contribution to journalArticlepeer-review

    25 Citations (Scopus)


    Nuclear actin and nuclear myosin I (NMI) are important players in transcription of ribosomal genes. Transcription of rDNA takes place in highly organized intranuclear compartment, the nucleolus. In this study, we characterized the localization of these two proteins within the nucleolus of HeLa cells with high structural resolution by means of electron microscopy and gold-immunolabeling. We demonstrate that both actin and NMI are localized in specific compartments within the nucleolus, and the distribution of NMI is transcription-dependent. Moreover, a pool of NMI is present in the foci containing nascent rRNA transcripts. Actin, in turn, is present both in transcriptionally active and inactive regions of the nucleolus and colocalizes with RNA polymerase I and UBF. Our data support the involvement of actin and NMI in rDNA transcription and point out to other functions of these proteins in the nucleolus, such as rRNA maturation and maintenance of nucleolar architecture.

    Original languageEnglish
    Pages (from-to)243-249
    Number of pages7
    JournalHistochemistry and Cell Biology
    Issue number3
    Publication statusPublished - 2010 Sep


    • Actin
    • Nuclear myosin I
    • Nucleolus
    • RNA polymerase I
    • Transcription
    • UBF

    ASJC Scopus subject areas

    • Histology
    • Molecular Biology
    • Medical Laboratory Technology
    • Cell Biology


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