2008年10月10日, 北京生命科學(xué)研究所馬力耕實驗室在 The Plant Cell 雜志上在線發(fā)表題為Histone H2B Monoubiquitination in the Chromatin of FLOWERING LOCUS C Regulates Flowering Time in Arabidopsis的文章, 報道了FLC(FLOWERING LOCUS C) 染色質(zhì)的一種新的修飾方式-H2B單泛素化調(diào)節(jié)FLC基因表達和擬南芥開花時間。
植物由營養(yǎng)生長向生殖生長轉(zhuǎn)化是植物的一個重要的發(fā)育過程。這種轉(zhuǎn)化發(fā)生在頂端分生組織細(xì)胞,，細(xì)胞分化的決定受多種因素調(diào)控,，其中轉(zhuǎn)錄因子FLC抑制營養(yǎng)生長向生殖生長的轉(zhuǎn)化，抑制程度與其表達水平成正相關(guān),。目前已知多種因素通過調(diào)控FLC染色質(zhì)的甲基化和乙?；瘉碚{(diào)控其表達,，而且FLC已經(jīng)成為植物體系中研究組蛋白修飾和基因表達調(diào)控之間關(guān)系的模型,。該論文鑒定了參與擬南芥組蛋白H2B單泛素化的E2和E3,，并證明FLC及其同源基因的染色質(zhì)H2B被單泛素化，H2B被單泛素化后進一步增強H3K4和H3K36的甲基化,，進而激活FLC及其同源基因的表達,，并導(dǎo)致開花延遲。這些E2和E3基因的突變導(dǎo)致植物開花提前,。該論文的研究結(jié)果證實FLC (FLOWERING LOCUS C) 染色質(zhì)的一種新的修飾-H2B單泛素化調(diào)節(jié)FLC基因表達并因此調(diào)控擬南芥開花時間,。
博士研究生曹穎和博士后戴艷為該文的共同第一作者。河北師范大學(xué)的崔素娟博士為本論文的合作者,。馬力耕博士為本文通訊作者,。 此項研究為科技部863和北京市科委資助課題，主要工作在北京生命科學(xué)研究所完成,。（生物谷Bioon.com）
生物谷推薦原始出處：
Plant Cell Published on October 10, 2008; 10.1105/tpc.108.062760
Histone H2B Monoubiquitination in the Chromatin of FLOWERING LOCUS C Regulates Flowering Time in Arabidopsis
Ying Cao 1, Yan Dai 2, Sujuan Cui 3, and Ligeng Ma 2
1 Institute of Molecular Cellular Biology, Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang 050016, China; National Institute of Biological Sciences, Beijing 102206, China
2 National Institute of Biological Sciences, Beijing 102206, China
3 Institute of Molecular Cellular Biology, Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang 050016, China
Ubiquitination is one of many known histone modifications that regulate gene expression. Here, we examine theArabidopsis thaliana homologs of the yeast E2 and E3 enzymes responsible for H2B monoubiquitination (H2Bub1).Arabidopsis has two E3 homologs (HISTONE MONOUBIQUITINATION1 [HUB1] and HUB2) and three E2 homologs (UBIQUITIN CARRIER PROTEIN [UBC1] to UBC3). hub1 and hub2 mutants show the loss of H2Bub1 and early flowering. By contrast, single ubc1, ubc2, or ubc3 mutants show no flowering defect; only ubc1 ubc2 double mutants, and not double mutants with ubc3, show early flowering and H2Bub1 defects. This suggests that ubc1 and ubc2 are redundant, but ubc3 is not involved in flowering time regulation. Protein interaction analysis showed that HUB1 and HUB2 interact with each other and with UBC1 and UBC2, as well as self-associating. The expression of FLOWERING LOCUS C (FLC) and its homologs was repressed in hub1, hub2, and ubc1 ubc2 mutant plants. Association of H2Bub1 with the chromatin of FLC clade genes depended on UBC1,2 and HUB1,2, as did the dynamics of methylated histones H3K4me3 and H3K36me2. The monoubiquitination of H2B via UBC1,2 and HUB1,2 represents a novel form of histone modification that is involved in flowering time regulation.
