Disease relevance of ELF3

• Here, we show conclusively that normal circadian function occurs with no alteration of period length in elf3 mutants in dark conditions and that the light-dependent arrhythmia observed in elf3 mutants is pleiotropic on multiple outputs normally expressed at different times of day [1].

High impact information on ELF3

• Furthermore, elf3 mutations confer the resetting pattern of short-day photoperiodism, indicating that gating of phototransduction may control resetting [2].
• The conditional arrhythmic phenotype suggests that the circadian pacemaker is intact in darkness in elf3 mutant plants, but the transduction of light signals to the circadian clock is impaired [3].
• Furthermore, the ELF3 protein interacts with PHYB in the yeast two-hybrid assay and in vitro [4].
• Overexpression of the LATE ELONGATED HYPOCOTYL gene, which has been proposed to function as a clock component, did not abolish circadian regulation of ELF3 transcription, providing further evidence that ELF3 is a circadian clock input pathway component [5].
• Plants overexpressing ELF3 have an increased period length in both constant blue and red light; furthermore, etiolated ELF3-overexpressing seedlings exhibit a decreased acute CAB2 response after a red light pulse, whereas the null mutant is hypersensitive to acute induction [1].

Biological context of ELF3

• Genetic analyses show that ELF3 requires PHYB function in early morphogenesis but not for the regulation of flowering time [4].
• ELF3 encodes a circadian clock-regulated nuclear protein that functions in an Arabidopsis PHYB signal transduction pathway [4].
• ELF3 was proposed to function as a modulator of light signal transduction downstream of phytochromes, and, perhaps, other photoreceptors [6].
• One has weaker morphological phenotypes than previously identified elf3 alleles, but still abolishes circadian rhythms under continuous light [7].
• The predicted amino acid sequence of the PYK20 protein contains 695 residues with a molecular mass of 78 kDa and includes a glutamine-rich domain in the C-terminal region [8].

Associations of ELF3 with chemical compounds

• Based on homologies of the glutamine-rich domain, the biological role of the pyk20 gene product as a transcription factor is assumed [8].
• IAA and kinetin treatment increased the level of the pyk20 transcript in the plant, whereas ABA treatment and temperature stress reduced the pyk20 transcript level [8].

Regulatory relationships of ELF3

• Recent work indicates that ELF3 encodes a novel nuclear protein that is expressed rhythmically and interacts with phytochrome B. How ELF3 mediates the circadian gating of light responses and regulates light input to the clock is the subject of discussion [6].

Other interactions of ELF3

• We have used this assay with wild-type and mutant seedlings to examine the role of these oscillator components, and to determine the function of ELF3 and ELF4 in their light-regulated expression [9].
• Here we show that the effects of ZTL and ELF3 on circadian clock function and early photomorphogenesis are additive [10].
• In contrast, ELF3 negatively regulates CO, FT, and GIGANTEA transcript levels, as the expression of all three genes is increased in elf3-1 [10].
• Lemna homologs of the Arabidopsis clock-related genes LHY/CCA1, GI, ELF3 and PRRs were then isolated as candidates for clock-related genes in these plants [11].
• Like phyB mutants, elf3 mutants have elongated hypocotyls and petioles, flower early, and have defects in the red light response [7].

Analytical, diagnostic and therapeutic context of ELF3

• Southern blot analysis revealed a single gene copy for pyk20 in the Arabidopsis C-24 genome [8].

References