The Dictyostelium bZIP transcription factor DimB regulates prestalk-specific gene expression

Natasha V. Zhukovskaya, Masashi Fukuzawa, Yoko Yamada, Tsuyoshi Araki, Jeffrey G. Williams

    Research output: Contribution to journalArticle

    48 Citations (Scopus)

    Abstract

    The ecmA gene is specifically expressed in prestalk cells and its transcription is induced by the chlorinated hexaphenone DIF-1. We have purified a novel bZIP transcription factor, DimB, by affinity chromatography on two spatially separated ecmA promoter fragments. Mutagenesis of the cap-site proximal DimB-binding site (the -510 site) greatly decreases ecmA expression in the pstO cells, which comprise the rear half of the prestalk zone, and also in the Anterior-Like Cells, which lie scattered throughout the prespore region. However, DimB is not essential for normal expression of the ecmA gene, instead it spatially limits its expression; ecmA is relatively highly expressed in the subset of prestalk cells that coats the prestalk zone, but in slugs of a DimB-null strain, ecmA is highly expressed throughout the prestalk zone. Because the -510 site is required for correct ecmA expression, we posit a separate activator protein that competes with DimB for binding to the -510 site. DimB rapidly accumulates in the nucleus when cells are exposed to DIF-1, and ChIP analysis shows that, in the presence of extracellular cAMP, DIF-1 causes DimB to associate with the ecmA promoter in vivo. Thus, DIF-1 regulates DimB activity to generate a gradient of ecmA expression in the prestalk zone of the slug.
    Original languageEnglish
    Pages (from-to)439-448
    Number of pages10
    JournalDevelopment
    Volume133
    Issue number3
    DOIs
    Publication statusPublished - Feb 2006

    Keywords

    • Dictyostelium
    • bZIP
    • Prestalk
    • DIF-1

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