Arabidopsis trithorax-related3/SET domain GROUP2 is required for the winter-annual habit of Arabidopsis thaliana.
Arabidopsis trithorax-related3/SET domain GROUP2 is required for the winter-annual habit of Arabidopsis thaliana.
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DOI：
10.1093/pcp/pcs021
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发表时间：
2012-05
影响因子：
4.9
通讯作者：
Jae-Young Yun;Yosuke Tamada;Ye Eun Kang;R. Amasino
中科院分区：
文献类型：
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作者：
Jae-Young Yun;Yosuke Tamada;Ye Eun Kang;R. Amasino
拟南芥的越冬习性需要开花基因C(FLC)和FRIGIDA(FRIGIDA)的活性等位基因。FLC被FRI激活伴随着特定的组蛋白修饰的增加，例如组蛋白H3在赖氨酸4(H3K4me3)的三甲基化，需要三个H3K4甲基转移酶，果蝇三胸类拟南芥1(ATX1)和ATX2，以及酵母Set1类ATX相关的7/SET结构域组25(ATXR7/SDG25)。然而，所有这些基因的损伤都不能完全抑制Fri引起的FLC表达的增强，提示另一种H3K4甲基转移酶可能参与了FLC的激活。在这里，我们发现ATXR3/SDG2是一类新的H3K4甲基转移酶的成员，它也参与了FLC的激活。在非春化植株中，ATXR3损伤抑制了由FRI活性等位基因引起的FLC表达增强和开花延迟。在atxr3突变体中，FLC表达的降低伴随着FLC染色质上H3K4me3水平的降低。我们还发现，atxr3的快速开花与atxr7的快速开花是上位的，这表明ATXR3与ATXR7在FLC激活中的作用顺序相同。我们的结果表明，新的H3K4甲基转移酶ATXR3是一种转录激活剂，在FLC的激活和建立越冬习性中发挥作用。此外，ATXR3还参与了其他FLC分支成员的激活，如影响开花1的开花基因M/MADS(Flm/MAF1)和MAF5，至少部分解释了ATXR3在非诱导光周期导致的延迟开花中的作用。
The winter-annual habit of Arabidopsis thaliana requires active alleles of flowering locus C (FLC), which encodes a potent flowering repressor, and FRIGIDA (FRI), an activator of FLC. FLC activation by FRI is accompanied by an increase in specific histone modifications, such as tri-methylation of histone H3 at lysine 4 (H3K4me3), and requires three H3K4 methyltransferases, the Drosophila Trithorax-class Arabidopsis trithorax1 (ATX1) and ATX2, and yeast Set1-class ATX-related7/set domain group25 (ATXR7/SDG25). However, lesions in all of these genes failed to suppress the enhanced FLC expression caused by FRI completely, suggesting that another H3K4 methyltransferase may participate in the FLC activation. Here, we show that ATXR3/SDG2, which is a member of a novel class of H3K4 methyltransferases, also contributes to FLC activation. An ATXR3 lesion suppressed the enhanced FLC expression and delayed flowering caused by an active allele of FRI in non-vernalized plants. The decrease in FLC expression in atxr3 mutants was accompanied by reduced H3K4me3 levels at FLC chromatin. We also found that the rapid flowering of atxr3 was epistatic to that of atxr7, suggesting that ATXR3 functions in FLC activation in sequence with ATXR7. Our results indicate that the novel-class H3K4 methyltransferase, ATXR3, is a transcriptional activator that plays a role in the FLC activation and establishing the winter-annual habit. In addition, ATXR3 also contributes to the activation of other FLC clade members, such as flowering locus M/MADS affecting flowering1 (FLM/MAF1) and MAF5, at least partially explaining the ATXR3 function in delayed flowering caused by non-inductive photoperiods.