Repression of the floral transition via histone H2B monoubiquitination

• Published in: The Plant journal : for cell and molecular biology Vol. 57; no. 3; pp. 522 - 533
• Main Authors: Gu, Xiaofeng, Jiang, Danhua, Wang, Yuqi, Bachmair, Andreas, He, Yuehui
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.02.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; Botany; Enzymes; FLC; FLC relatives; flowering; Flowers & plants; Flowers - enzymology; Flowers - genetics; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Genetics; H2B monoubiquitination; Histones - metabolism; MADS Domain Proteins - metabolism; Plant physiology and development; RNA, Plant - genetics; ubiquitin-conjugating enzyme; Ubiquitin-Conjugating Enzymes - genetics; Ubiquitin-Conjugating Enzymes - metabolism; Ubiquitin-Protein Ligases - metabolism; Ubiquitination; Vegetative and sexual reproduction, floral biology, fructification; Ubiquitin; FLC relatives; Histone H2B; Enzyme; ubiquitin-conjugating enzyme; Repression; Gene expression; Floral transition; Arabidopsis thaliana; Regulation(control); Cruciferae; Dicotyledones; Angiospermae; H2B monoubiquitination; Flowering; Spermatophyta; Experimental plant; FLC
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313x.2008.03709.x

The Rad6-Bre1 complex monoubiquitinates histone H2B in target gene chromatin, and plays an important role in positively regulating gene expression in yeast. Here, we show that the Arabidopsis relatives of the yeast Rad6, ubiquitin-conjugating enzyme 1 (UBC1) and UBC2, redundantly mediate histone H2B monoubiquitination, and upregulate the expression of FLOWERING LOCUS C (FLC; a central flowering repressor in Arabidopsis) and FLC relatives, and also redundantly repress flowering, the developmental transition from a vegetative to a reproductive phase that is critical in the plant life cycle. Moreover, we have found that Arabidopsis relatives of the yeast Bre1, including HISTONE MONOUBIQUITINATION 1 (HUB1) and HUB2, also upregulate the expression of FLC and FLC relatives, and that HUB1 genetically interacts with UBC1 and UBC2 to repress the floral transition. These findings are consistent with a model in which HUB1 and HUB2 specifically interact with and direct UBC1 and UBC2 to monoubiquitinate H2B in developmental genes, and thus regulate developmental processes in plants.