Vertebrate Spt2 is a novel nucleolar histone chaperone that assists in ribosomal DNA transcription

Akihisa Osakabe, Hiroaki Tachiwana, Motoki Takaku, Tetsuya Hori, Chikashi Obuse, Hiroshi Kimura, Tatsuo Fukagawa, Hitoshi Kurumizaka*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    20 Citations (Scopus)


    In eukaryotes, transcription occurs in the chromatin context with the assistance of histone-binding proteins, such as chromatin/nucleosome remodeling factors and histone chaperones. However, it is unclear how each remodeling factor or histone chaperone functions in transcription. Here, we identify a novel histone-binding protein, Spt2, in higher eukaryotes. Recombinant human Spt2 binds to histones and DNA, and promotes nucleosome assembly in vitro. Spt2 accumulates in nucleoli and interacts with RNA polymerase I in chicken DT40 cells, suggesting its involvement in ribosomal RNA transcription. Consistently, Spt2-deficient chicken DT40 cells are sensitive to RNA polymerase I inhibitors and exhibit decreased transcription activity, as shown by a transcription run-on assay. Domain analyses of Spt2 revealed that the C-terminal region, containing the region homologous to yeast Spt2, is responsible for histone binding, while the central region is essential for nucleolar localization and DNA binding. Based on these results, we conclude that vertebrate Spt2 is a novel histone chaperone with a separate DNA-binding domain that facilitates ribosomal DNA transcription through chromatin remodeling during transcription.

    Original languageEnglish
    Pages (from-to)1323-1332
    Number of pages10
    JournalJournal of Cell Science
    Issue number6
    Publication statusPublished - 2013 Mar 15


    • Chromatin
    • Histone chaperone
    • Nucleoli
    • Nucleosome
    • RNA polymerase
    • Transcription

    ASJC Scopus subject areas

    • Cell Biology


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