Anti-Amyloid Precursor Protein polyclonal antibody

In plants, seasonal inputs such as photoperiod and temperature modulate the plant's internal genetic program to regulate the timing of the developmental transition from vegetative to reproductive growth. This regulation of the floral transition involves chromatin remodeling, including covalent modification of histones. Here, we report that HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENE 15 (HOS15), a WD40 repeat protein, associates with a histone deacetylase complex to repress transcription of the GIGANTEA (GI)-mediated photoperiodic flowering pathway in Arabidopsis (Arabidopsis thaliana). Loss of function of HOS15 confers early flowering under long-day conditions because elevated GI expression. LUX ARRHYTHMO (LUX), a DNA binding transcription factor and component of the Evening Complex (EC), is important for the binding of HOS15 to the GI promoter. In wild type, HOS15 associates with the EC components LUX, EARLY FLOWERING 3 (ELF3), and ELF4 and the histone deacetylase HDA9 at the GI promoter, resulting in histone deacetylation and reduced GI expression. In the hos15-2 mutant, the levels of histone acetylation are elevated at the GI promoter, resulting in increased GI expression. Our data suggest that the HOS15-EC-HDA9 histone-modifying complex regulates photoperiodic flowering via the transcriptional repression of GI.

Plant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana (Arabidopsis) and crop species, circadian clock factors are critical for growth, flowering, and circadian rhythms. Outside of Arabidopsis, however, little is known about the molecular function of clock gene products. Therefore, we sought to compare the function of Brachypodium distachyon (Brachypodium) and Setaria viridis (Setaria) orthologs of EARLY FLOWERING 3, a key clock gene in Arabidopsis. To identify both cycling genes and putative ELF3 functional orthologs in Setaria, a circadian RNA-seq dataset and online query tool (Diel Explorer) were generated to explore expression profiles of Setaria genes under circadian conditions. The function of ELF3 orthologs from Arabidopsis, Brachypodium, and Setaria was tested for complementation of an elf3 mutation in Arabidopsis. We find that both monocot orthologs were capable of rescuing hypocotyl elongation, flowering time, and arrhythmic clock phenotypes. Using affinity purification and mass spectrometry, our data indicate that BdELF3 and SvELF3 could be integrated into similar complexes in vivo as AtELF3. Thus, we find that, despite 180 million years of separation, BdELF3 and SvELF3 can functionally complement loss of ELF3 at the molecular and physiological level.