Publications (2)21.1 Total impact
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Article: A stress surveillance system based on calcium and nitric oxide in marine diatoms.
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ABSTRACT: Diatoms are an important group of eukaryotic phytoplankton, responsible for about 20% of global primary productivity. Study of the functional role of chemical signaling within phytoplankton assemblages is still in its infancy although recent reports in diatoms suggest the existence of chemical-based defense strategies. Here, we demonstrate how the accurate perception of diatom-derived reactive aldehydes can determine cell fate in diatoms. In particular, the aldehyde (2E,4E/Z)-decadienal (DD) can trigger intracellular calcium transients and the generation of nitric oxide (NO) by a calcium-dependent NO synthase-like activity, which results in cell death. However, pretreatment of cells with sublethal doses of aldehyde can induce resistance to subsequent lethal doses, which is reflected in an altered calcium signature and kinetics of NO production. We also present evidence for a DD-derived NO-based intercellular signaling system for the perception of stressed bystander cells. Based on these findings, we propose the existence of a sophisticated stress surveillance system in diatoms, which has important implications for understanding the cellular mechanisms responsible for acclimation versus death during phytoplankton bloom successions.PLoS Biology 04/2006; 4(3):e60. · 11.45 Impact Factor -
Article: The photomorphogenesis regulator DET1 binds the amino-terminal tail of histone H2B in a nucleosome context.
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ABSTRACT: Light provides a major source of information from the environment during plant growth and development. Recent results suggest that the key events controlling light-regulated gene expression in plants are translocation of the phytochrome photoreceptors into the nucleus, followed by their binding to transcription factors such as PIF3. Coupled with this, the degradation of positively acting intermediates such as the transcription factor HY5 by COP1 and the COP9 signalosome appears to be an important process whereby photomorphogenesis is repressed in darkness (e.g., ). Genetic analyses in Arabidopsis and tomato have revealed that the nuclear protein DET1 also plays a key role in the repression of photomorphogenesis. However, the function of this protein has remained a mystery. In a series of in vitro experiments, we provide persuasive evidence that DET1 binds to nonacetylated amino-terminal tails of the core histone H2B in the context of the nucleosome. Furthermore, we have utilized FRET (fluorescence resonance energy transfer) imaging with GFP variants to demonstrate this interaction within the nucleus of living plant cells. Given the dramatic photomorphogenic phenotypes of det1 mutants, we propose that chromatin remodeling plays a heretofore unsuspected role in regulating gene expression during photomorphogenesis.Current Biology 10/2002; 12(17):1529-34. · 9.65 Impact Factor
