First published online April 12, 2006
Development 133, 903e (2006)
© The Company of Biologists Limited
Chipping away at flowering
In another study about the switch to flowering (p.
1693), Lars Hennig and
colleagues investigate the protein MULTICOPY SUPRESSOR OF IRA1 (MSI1). MSI1 is
a component of the fertilization independent seed complex (FIS), which
resembles the Drosophila Polycomb complex PRC2. The process of
flowering is controlled by three main pathways that converge to regulate a
protein called SOC1, which is repressed by the potent flowering inhibitor
FLOWERING LOCUS C (FLC). First, the authors showed that MSI1 activates the
floral transition: msi1 mutants had a late flowering phenotype, and
transgenic plants with increased MSI1 levels flowered early. Then, analysis of
msi1 soc1 double mutants demonstrated that MSI1 acts upstream of
SOC1. But by what mechanism? Because FIS is involved in chromatin regulation,
they investigated this using chromatin immunoprecipitation (ChIP) assays, and
found that MSI1 is required for the H3K4 methylation and H3K9 acetylation of
SOC1 chromatin. Chromatin modifications are known to be involved in
the regulation of FLC; now, the authors conclude that MSI1 regulates
SOC1 in a similar way.
Related articles in Development:
- Regulation of flowering time by Arabidopsis MSI1
- Romaric Bouveret, Nicole Schönrock, Wilhelm Gruissem, and Lars Hennig
Development 2006 133: 1693-1702.
[Abstract]
[Full Text]
