PT  - JOURNAL ARTICLE
AU  - Valverde, Federico
AU  - Mouradov, Aidyn
AU  - Soppe, Wim
AU  - Ravenscroft, Dean
AU  - Samach, Alon
AU  - Coupland, George
TI  - Photoreceptor Regulation of CONSTANS Protein in Photoperiodic Flowering
AID  - 10.1126/science.1091761
DP  - 2004 Feb 13
TA  - Science
PG  - 1003--1006
VI  - 303
IP  - 5660
4099  - http://science.sciencemag.org/content/303/5660/1003.short
4100  - http://science.sciencemag.org/content/303/5660/1003.full
SO  - Science2004 Feb 13; 303
AB  - Many plants flower in response to seasonal fluctuations in day length. The CONSTANS (CO) gene of Arabidopsis promotes flowering in long days. Flowering is induced when CO messenger RNA expression coincides with the exposure of plants to light. However, how this promotes CO activity is unknown. We show that light stabilizes nuclear CO protein in the evening, whereas in the morning or in darkness the protein is degraded by the proteasome. Photoreceptors regulate CO stability and act antagonistically to generate daily rhythms in CO abundance. This layer of regulation refines the circadian rhythm in CO messenger RNA and is central to the mechanism by which day length controls flowering.