The Plant Journal · 2001 · 292 citations · 27 references
Life SciencesPlant BiologyPlant SciencesCircadian RhythmsPlant GeneticsPlant Molecular BiologyCircadian Clock MechanismsCircadian Gene ExpressionCircadian Molecular MechanismsCircadian PhysiologyPlant Transcriptional RegulationCircadian ClocksCircadian Regulation Of Gene ExpressionCircadian Rhythm Gene ExpressionCircadian Transcriptional ControlCircadian Transcriptional RegulationFlowering Time RegulationTransgenic PlantsZinc Finger Proteins
The Arabidopsis genes CONSTANS-LIKE 1 (COL1) and CONSTANS-LIKE 2 (COL2) are predicted to encode zinc finger proteins with approximately 67% amino acid identity to the protein encoded by the flowering-time gene CONSTANS (CO). We show that the circadian clock regulates expression of COL1 and COL2 with a peak in transcript levels around dawn. We analyzed transgenic plants misexpressing COL1, COL2 and CO. Unlike CO, altered expression of COL1 and COL2 in transgenic plants had little effect on flowering time. However, analysis of circadian phenotypes in the transgenic plants showed that over-expression of COL1 can shorten the period of two distinct circadian rhythms. Experiments with the highest COL1 over-expressing line indicate that its circadian defects are fluence rate-dependent, suggesting an effect on a light input pathway(s).
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Dirk Valvekens, Marc Van Montagu, Mieke Van Lijsebettens · Proceedings of the National Academy of Sciences · 1988 · 1.3K citations · Full text