Abstract
In higher plants, many biological processes are rhythmically controlled through the circadian clock. For the model plant Arabidopsis thaliana, a certain number of clock-asscociated genes (e.g., CCA1/LHY, ELF4, LUX) were already reported. We also proposed that a set of pseudo-response regulators (PRRs) play essential roles close to the central oscillator. In our previous studies, however, we examined the expression profiles of these clock-associated PRR genes mainly at the level of transcription. Thus, better clarification of the molecular functions of PRRs must await examination of PRRs at the level of protein (translation and degradation). To this end, here we constructed and characterized a set of transgenic plants, which expressed epitope-tagged PRRs (e.g., TAP-PRR9), demonstrating that they indeed showed robust rhythms with reference to the protein profile. Based on these results, the possibility was also examined whether a clock-complex containing PRRs could be biochemically isolated.
