AUTHOR=Li Jian , Wang Zheng , Hu Yugang , Cao Ying , Ma Ligeng 

TITLE=Polycomb Group Proteins RING1A and RING1B Regulate the Vegetative Phase Transition in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00867

DOI=10.3389/fpls.2017.00867

ISSN=1664-462X

ABSTRACT=<p>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 <italic>Arabidopsis</italic>. The mutation of RING1A/B increased the expression of members of the <italic>SQUAMOSA PROMOTER BINDING PROTEIN-LIKE</italic> (<italic>SPL</italic>) gene family and caused an early vegetative phase transition. The early vegetative phase transition observed in <italic>ring1a ring1b</italic> double mutant plants was dependent on an <italic>SPL</italic> family gene, and the H2Aub status of the chromatin at <italic>SPL</italic> 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 <italic>Arabidopsis</italic>. Together, our results demonstrate that RING1A/B regulates the vegetative phase transition in <italic>Arabidopsis</italic> through the repression of <italic>SPL</italic> family genes.</p>