Fig. 5

Long noncoding RNA-mediated regulation of DNA and histone methylation in plants and animals uncovers mechanistic commonalities across kingdoms. A Model for the regulation of YUC2 expression in response to heat by the APOLO-VIM1-LHP1 complex: at 23 °C, APOLO lncRNA recognizes the YUCCA2 (YUC2) locus by sequence complementarity and R-loop formation. APOLO interacts with VIM1 and LHP1 over the YUC2 promoter region, which exhibits RdDM and H3K27me3 deposition, blocking YUC2 transcription. meDNA (light brown balls) and H3K27me3 (dark brown balls) are cooperatively maintained by the VIM1-LHP1 complex. At 29 °C, APOLO transcript levels decrease and VIM1-LHP1 binding to the YUC2 promoter region is reduced. Conjointly, 24nt siRNA accumulation is decreased, impairing RdDM over the YUC2 promoter. As a result, YUC2 transcriptional activity increases. YUC2 participates in auxin synthesis, promoting hypocotyl elongation in response to heat. B Proposed explanation for the molecular impact of APOLO or UPAT constitutive expression. Although the ability of UPAT to form R-loops in animals (or when expressed in plants) remains unknown, high levels of both lncRNAs in Arabidopsis achieve to decoy VIM1 and LHP1 away from chromatin, hinting at a stoichiometrically modulated mechanism. C Comparison between conserved lncRNA-integrated epigenetic machineries across kingdoms. Homolog proteins between Homo sapiens and Arabidopsis thaliana are shown in the same color. References of the articles demonstrating direct interactions or co-localizations are indicated. Question marks “?” mean that the interaction has not been proved yet