Enhancement of blue-light sensitivity of Arabidopsis seedlings by a blue light receptor cryptochrome 2
- *Department of Molecular, Cell and Developmental Biology, and Molecular Biology Institute, University of California, Los Angeles, CA 90095; and †Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, PA 19104
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Communicated by Bernard O. Phinney, University of California, Los Angeles, CA (received for review November 18, 1997)
Abstract
Cryptochrome is a group of flavin-type blue light receptors that regulate plant growth and development. The function of Arabidopsis cryptochrome 2 in the early photomorphogenesis of seedlings was studied by using transgenic plants overexpressing CRY2 protein, and cry2 mutant plants accumulating no CRY2 protein. It is found that cryptochrome 2 mediates blue light-dependent inhibition of hypocotyl elongation and stimulation of cotyledon opening under low intensities of blue light. In contrast to CRY1, the expression of CRY2 is rapidly down-regulated by blue light in a light-intensity dependent manner, which provides a molecular mechanism to explain at least in part that cryptochrome 2 functions primarily under low light during the early development of seedlings.
Footnotes
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↵ ‡ To whom reprint requests should be addressed at: Department of Molecular, Cell, and Developmental Biology, University of California, 621 Circle Drive South, Los Angeles, CA 90095-1606. e-mail: clin{at}mcdb.ucla.edu.
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Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. U43397).
- Copyright © 1998, The National Academy of Sciences
