Oscillation of mRNA level and activity of granule-bound starch synthase I in Arabidopsis leaves during the day/night cycle.

摘要: Granule-bound starch synthase (GBSSI) is one of the most extensively studied enzymes synthesis pathway and its role in amylose has been well established. However, few studies have carried out to characterize regulation GBSSI gene. Regulation genes especially interesting photosynthetic tissues, where subjected a periodical alternation degradation during day/night cycle. In this report we show circadian oscillation mRNA levels leaves Arabidopsis cycle, provide evidence that expression controlled by transcription factors CCA1 LHY. Over-expression both LHY causes elimination oscillation. Binding shift assays indicate control may be exerted through direct interaction those regulatory proteins with promoter. Oscillation not observed on protein levels, which remains constant along activity shows clear period 24 h altered transgenic plants over-expressing CCA1. Possible mechanisms controlling cycle are discussed.