Polycomb Group Proteins RING1A and RING1B Regulate the Vegetative Phase Transition in .

Polycomb group (PcG) protein-mediated gene silencing is a major regulatory mechanism in higher eukaryotes that affects gene expression at the transcriptional level. Here, we report that two conserved homologous PcG proteins, RING1A and RING1B (RING1A/B), are required for global H2A monoubiquitination (H2Aub) in . The mutation of RING1A/B increased the expression of members of the () gene family and caused an early vegetative phase transition. The early vegetative phase transition observed in double mutant plants was dependent on an family gene, and the H2Aub status of the chromatin at locus was dependent on RING1A/B. Moreover, mutation in RING1A/B affected the miRNA156a-mediated vegetative phase transition, and RING1A/B and the AGO7-miR390-TAS3 pathway were found to additively regulate this transition in . Together, our results demonstrate that RING1A/B regulates the vegetative phase transition in through the repression of family genes.