TheLNK1night light-inducible and clock-regulated gene is induced also in response to warm-night through the circadian clock nighttime repressor inArabidopsis thaliana

Abstract

Ambient temperature has two fundamental impacts on the Arabidopsis circadian clock system in the processes referred to as temperature compensation and entrainment, respectively. These temperature-related longstanding problems have not yet been fully clarified. Recently, we provided evidence that temperature signals feed into the clock transcriptional circuitry through the evening complex (EC) nighttime repressor composed of LUX-ELF3-ELF4, and that the transcription of PRR9, PRR7, GI and LUX is commonly regulated through the nighttime repressor in response to both moderate changes in temperature (∆6 °C) and differences in steady-state growth-compatible temperature (16 °C to 28 °C). These temperature-associated characteristics of the core clock genes might be relevant to the fundamental oscillator functions. Here, we further show that the recently identified LNK1 night light-inducible and clock-controlled gene, which actually has a robust peak at daytime, is induced also by warm-night through the EC nighttime repressor in a manner very similar to PRR7, which is also night light-inducible daytime gene. Based on these findings, a hypothetical view is proposed with regard to the temperature entrainment of the central oscillator.

Time-dependent sequestration of RVE8 by LNK proteins shapes the diurnal oscillation of anthocyanin biosynthesis

“…S4). Similar to the RVE8 oscillation, the expression of LNKs rhythmically oscillate under LD cycles and under LL conditions with a peak close to dawn (20)(21)(22). Analysis of the RVE8 coexpressed gene network uncovered the members of the LNK family as highly significant genes coexpressed with RVE8 (SI Appendix, Fig.…”

“…Recent studies have identified the NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED genes (LNK) as key circadian components with an important role in seasonal adjustment (20). The LNKs integrate environmental signals to control the expression of afternoon genes, allowing plants to perceive and respond to seasonal changes in day length and temperature (20)(21)(22). Two members of the LNK family (LNK1 and LNK2) interact with RVE8 and RVE4 and form a protein complex that is important for the transcriptional activation of the evening-phased clock genes, PRR5 and TOC1 (21).…”

Targeted Recruitment of the Basal Transcriptional Machinery by LNK Clock Components Controls the Circadian Rhythms of Nascent RNAs in Arabidopsis

“…In addition to altered gene expression, plants misexpressing RVE8 and/ or LNKs show a variety of phenotypes affecting anthocyanin accumulation, plant growth, and photoperiodic regulation of flowering time (Farinas and Mas, 2011;Rawat et al, 2011;Pérez-García et al, 2015;Gray et al, 2017). Overall, LNKs connect circadian gene expression, growth, and development with seasonal changes in daylength and temperature (Rugnone et al, 2013;Mizuno et al, 2014;Xie et al, 2014).…”

Making the clock tick: the transcriptional landscape of the plant circadian clock

“…The EC represses the morning-expressed PRR7 and PRR9 and evening-expressed GIGANTEA (GI) and LUX 29– 34 . LUX and ELF3 have also been recently shown to associate with the promoter of LNK1/2 , highlighting another potential target of the EC 35 . Together, this interconnected network of activators and repressors drives rhythmic gene expression within the plant oscillator.…”