Characterization of circadian-associated pseudo-response regulators: II. The function of PRR5 and its molecular dissection in Arabidopsis thaliana.
Together with PRR1/TOC1, PRR5 belongs to the small family of Pseudo-Response Regulators (PRRs), which function as clock components of Arabidopsis thaliana. We employed a set of transgenic lines, each of which was designed to misexpress a truncated form of the PRR5 molecule, together with the original transgenic line (named PRR5-ox) that misexpresses the entire PRR5 polypeptide. The results of genetic analysis suggested that PRR5-ox seedlings showed a phenotype of hypersensitivity to red light during early photomorphogenesis in a manner dependent on red light photoreceptors (PhyA and PhyB), but independent of PRR1/TOC1. The set of newly constructed transgenic lines (named PRR5-N-ox and PRR5-C-ox) were also characterized in terms of circadian-associated phenotypes. The results suggest that the N-terminal pseudo-receiver domain of the PRR5 molecule seems to be dispensable for the misexpressed PRR5 molecule to bring about the phenotype of red light sensitivity. However, PRR5-N-ox plants, misexpressing only the pseudo-receiver domain, showed a phenotype of long period of free-running circadian rhythms of certain clock-controlled genes. Considering these and other results, we discuss the structure and function of PRR5 in the context of current views of the circadian clock in higher plants.
Matsushika
Akinori
A
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Furocho, Nagoya, Japan.
Kawamura
Masakazu
M
Nakamura
Yuko
Y
Kato
Takahiko
T
Murakami
Masaya
M
Yamashino
Takafumi
T
Mizuno
Takeshi
T
D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000502:physiology*; D015152:Blotting, Northern; D002940:Circadian Rhythm / Q000235:genetics* / Q000502:physiology*; D008027:Light; D010775:Photic Stimulation; D011523:Protoplasts / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000502:physiology
D029681:Arabidopsis Proteins; C511731:PRR3 protein, Arabidopsis; D014157:Transcription Factors