High impact information on LHY

• Furthermore, the expression of both endogenous CCA1 and the related LHY gene was suppressed [1].
• Thus, constant expression of LHY disrupts several distinct circadian rhythms in Arabidopsis, and LHY may be closely associated with the central oscillator of the circadian clock [2].
• Increased LHY expression from a transgene caused the endogenous gene to be expressed at a constant level, suggesting that LHY was part of a feedback circuit that regulated its own expression [2].
• The dominant late elongated hypocotyl (lhy) mutation of Arabidopsis disrupted circadian clock regulation of gene expression and leaf movements and caused flowering to occur independently of photoperiod [2].
• The MYB transcription factors LHY and CCA1 negatively regulate TOC1 expression [3].

Biological context of LHY

• Unexpectedly, translational induction coincided with acute downregulation of LHY transcript levels [4].
• In addition, we demonstrate that two other circadian rhythm mutants, LHY-ox and elf3, have low-viability phenotypes [5].
• The daily onset of LHY gene expression was advanced by approximately 4 h in det1-1 mutant plants, suggesting that the wild-type DET1 protein might function to repress its transcription during the subjective night. lhy-1 det1-1 double mutants exhibited arrhythmic expression of the CAB gene in constant light, similar to the lhy-1 mutant parent [6].
• Furthermore, binding assays with Arabidopsis (Arabidopsis thaliana) late elongated hypocotyl, a transcription factor of Arabidopsis involved in circadian regulation, clearly revealed the presence of circadian-determining regulatory elements in the promoter region of PcISPS [7].

Regulatory relationships of LHY

• DET1 regulates the proteasomal degradation of LHY, a component of the Arabidopsis circadian clock [6].

Other interactions of LHY

• ELF3 is also necessary for light-induced CCA1/LHY expression, but it is neither light-induced nor clock-regulated during de-etiolation [8].
• Transfer to constant red light (Rc) rapidly induces a biphasic pattern of CCA1 and LHY expression, and a reciprocal TOC1 expression pattern over the first 24 h, consistent with initial induction of this synchronous oscillation by the light signal [8].
• As previously reported, the gi-2 mutation affects the period length and amplitude of CCA1 and LHY expression, and GI may act through a feedback loop to maintain a proper circadian function [9].
• Here we show that plants overexpressing CKB3, a regulatory subunit of CK2, display increased CK2 activity and shorter periods of rhythmic expression of CCA1 and LHY [10].
• Over-expression of both CCA1 and LHY genes causes the elimination of GBSSI mRNA oscillation [11].

References