title: The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: II. Characterization with CCA1-overexpressing plants.
abstract: We previously identified a novel class of proteins, named pseudo-response regulators (APRRs) in Arabidopsis thaliana, each of which (APRR1, APRR3, APRR5, APRR7, and APRR9) has an intriguing structural design containing an N-terminal pseudo receiver domain and a C-terminal CONSTANS motif. Among them, APRR1 is identical to TOC1, previously proposed to be a candidate component of an Arabidopsis circadian clock. Intriguingly, expressions of the APRR1/TOC1 family of genes are under control of coordinate circadian rhythms at the level of transcription, in the manner that each APRR-transcript starts accumulating sequentially after dawn with 2 to 3 h intervals in the order: APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we examined this circadian-related event, "circadian waves of the APRR1/TOC1 quintet", by employing CCA1-overexpression (CCA1-ox) transgenic plants, based on the fact that CCA1 is a well-characterized and the most plausible oscillator component. It was found that aberrant overexpression of the CCA1 gene severely perturbed free-running and sequential rhythms of the APRR1/TOC1 family of genes. In the accompanying paper, it was shown that overexpression of APRR1 also results in a marked alteration of the CCA1 circadian rhythm, and vice versa. Taken together, it was suggested that there are intimate and mutual links between these two types of circadian-associated components (APRRs and CCA1).
authors.affiliation: Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya, 464-8601 Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Matsushika
authors.forename: Seiya
authors.initials: S
authors.lastname: Makino
authors.forename: Masaya
authors.initials: M
authors.lastname: Kojima
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamashino
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizuno
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics; D015152:Blotting, Northern; D002940:Circadian Rhythm / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: C091601:ABI3 protein, Arabidopsis; C448162:APRR3 protein, Arabidopsis; C448160:APRR5 protein, Arabidopsis; C448161:APRR7 protein, Arabidopsis; C448159:APRR9 protein, Arabidopsis; D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; D010940:Plant Proteins; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors