The transcription factor RSG regulates negative feedback of NtGA20ox1 encoding GA 20-oxidase

Jutarou Fukazawa, Masaru Nakata, Takeshi Ito, Shinjiro Yamaguchi, Yohsuke Takahashi

    Research output: Contribution to journalArticlepeer-review

    37 Citations (Scopus)


    Summary Gibberellins (GAs) are phytohormones that regulate growth and development throughout the life cycle of plants. RSG (REPRESSION OF SHOOT GROWTH) is a tobacco (Nicotiana tabacum) transcriptional activator with a basic leucine zipper domain that regulates the endogenous amount of GAs by control of GA biosynthetic enzymes. Negative feedback contributes to homeostasis of the GA levels. Previous studies suggested that RSG is directly or indirectly involved in the GA negative feedback of NtGA20ox1 encoding GA 20-oxidase. Using transgenic tobacco plants, we have identified a cis-acting region that is responsible for the feedback regulation of NtGA20ox1. This region contains an RSG-binding sequence. A mutation in the RSG-binding sequence abolished negative feedback of NtGA20ox1 in transgenic plants. Chromatin immunoprecipitation (ChIP) assays showed that RSG binds to the NtGA20ox1 promoter in vivo in response to a decrease in GA levels, and that this binding is abolished within 3 h after GA treatment. Furthermore, decreases in GA levels promote modifications of active histone marks in the promoter of NtGA20ox1. Our results suggest that RSG plays a role in the homeostasis of GAs through direct binding to the NtGA20ox1 promoter.

    Original languageEnglish
    Pages (from-to)1035-1045
    Number of pages11
    JournalPlant Journal
    Issue number6
    Publication statusPublished - 2010 Jun


    • Feedback regulation
    • GA 20-oxidase
    • Gibberellin biosynthesis
    • Histone modification
    • Tobacco

    ASJC Scopus subject areas

    • Genetics
    • Plant Science
    • Cell Biology


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