Light to dark transition modulates the phase of antenna chlorophyll protein gene expression.
The genes coding for the light-harvesting chlorophyll a/b-binding protein of photosystem II (cab) in wheat are regulated by phytochrome and an endogenous circadian clock. The regulation by these factors has been shown to be at the transcriptional level. Here we show that the phase of cab gene expression is reset by light to dark transition of the previous day. The time of light to dark transition is linearly related to the time of maximal cab gene expression under free running conditions in darkness. We propose that in nature the onset of darkness resets the phase of the circadian clock, which regulates the timing of cab gene expression, so as to anticipate the time of sunrise in the following day.
Lam
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Laboratory of Plant Molecular Biology, Rockefeller University, New York, New York 10021.
Chua
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NH
D002734:Chlorophyll / Q000235:genetics*; D003624:Darkness; D005786:Gene Expression Regulation / Q000528:radiation effects; D017343:Genes, Plant; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics; D014908:Triticum / Q000235:genetics
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll