背景回顾：FLM is a well-known MADS-box transcription factor that is required for preventing early flowering under low temperatures in Arabidopsis thaliana. Alterative splicing of FLM is involved in the regulation of temperature-responsive flowering. 

提出问题：However, it is largely unknown how the basic transcript level of FLM is regulated. 

主要发现：Here, we conducted forward genetic screening and identified a previously uncharacterized flowering repressor gene, UBA2c. 

结果1-UBA2c-FLM：Genetic analyses indicated that UBA2c represses flowering at least by promoting FLM transcription. We further demonstrated that UBA2c directly binds to FLM chromatin and facilitates FLM transcription by inhibiting histone H3K27 trimethylation, a histone mark related to transcriptional repression.

结果2-UBA2c结构域与功能：UBA2c encodes a protein containing two putative RNA recognition motifs (RRMs) and one prion-like domain (PrLD). We found that UBA2c forms speckles in the nucleus and that both the RRMs and PrLD are required not only for forming the nuclear speckles but also for the biological function of UBA2c. 

结论：These results identify a previously unknown flowering repressor and provide insights into the regulation of flowering time.

 摘 要 

FLM是一个比较有名的MADS-box转录因子，在拟南芥中主要作用于防止低温环境下植株的提前开花。FLM的可变剪切参与温度响应的开花调控。但是，FLM在转录层面的调控机制还不清楚。本文中，作者通过正向遗传学筛选，鉴定到了之前未曾发现的一个开花抑制因子UBA2c。遗传分析发现UBA2c通过促进FLM的转录来抑制开花。作者进一步发现UBA2c能够直接结合到FLM染色质，并通过抑制组蛋白H3K27三甲基化（即一种与转录抑制相关的组蛋白标记）来促进FLM的转录。UBA2c编码的蛋白含有两个RNA识别基序（RRM）和一个类阮蛋白结构域（PrLD）。作者发现UBA2c在细胞核中形成散斑，并且两个RRMs和PrLD结构域都是UBA2c形成核散斑所必需的，同时也是UBA2c发挥其生物学功能所必需的。本文的研究结果鉴定了一个先前未知的开花抑制因子，为植物的开花时间调控提供了新的视野。