Submitted to: The Plant Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2002
Publication Date: 5/1/2002
Interpretive Summary: This article reports results that advance our understanding of how a gene named CLAVATA3 (CLV3) functions in Arabidopsis development. CLV3 prevents plants from forming more cells in their stems and flowers than they need for normal growth. We used a series of assays to show that the CLV3 protein travels out of the stem and flower cells in which it is made, in order to signal to other nearby cells that they should not accumulate too fast. Our results reveal a mechanism through which cells communicate information to one another that may be widely used in plant systems.
Technical Abstract: Plant growth and development depends upon the activity of a continuously replenished pool of stem cells within the shoot apical meristem to supply cells for organogenesis. In Arabidopsis, the stem cell-specific protein CLAVATA3 (CLV3) acts cell nonautonomously to restrict the size of the stem cell population, but the hypothesis that CLV3 acts as an extracellular signaling molecule has not been tested. We used genetic and immunological assays to show that CLV3 localizes to the apoplast and that export to the extracellular space is required for its function in activating the CLV1/CLV2 receptor complex. Apoplastic localization allows CLV3 to signal from the stem cell population to the organizing center in the underlying cells.