背景回顾：Non-coding transcription is present in all eukaryotic genomes, but we lack fundamental knowledge about its importance for an organism’s ability to develop properly. In plants, emerging evidence highlights the essential biological role of non-coding transcription in regulating coding transcription. 

提出问题：However, the molecular insights into the regulation are largely unknown. 

结果：Here, we show that a long isoform of the long non-coding RNA, SVALKA-L (SVK-L), forms a natural antisense transcript to the host gene CBF1 and negatively regulates CBF1 mRNA levels at normal temperatures in the model plant Arabidopsis thaliana. Furthermore, we show detailed evidence for the specific mode of action for SVK-L. This pathway includes the formation of double stranded RNA that is recognized by the DICER proteins and subsequent down-regulation of CBF1 mRNA levels. 

结论：Thus, the CBF1-SVK regulatory circuit is not only important for the previously known role in cold temperature acclimation but also for biomass production at normal temperatures. 

展望：Our study characterizes a developmental role of SVK-L and offers mechanistic insight into how biologically important overlapping natural antisense transcripts can act on and fine-tune the steady state levels of their host gene’s mRNA.

 摘 要 

非编码转录存在于所有的真核生物中，但是我们仍缺少对其在生物个体正常发育过程中发挥功能重要性的理解。在植物中，越来越多的证据表明非编码转录在调控编码转录中的重要生物学功能。但是，对于该调控在分子层面的理解仍然有所局限。本文中，作者在拟南芥中发现一个长链非编码RNA（SVALKA）的长异构体SVK-L形成了一个其宿主基因CBF1基因的天然反义转录本，能够在常温条件下负调控CBF1基因的mRNA水平。此外，作者还发现了SVK-L具体作用模式的详细证据。该途径包括能够被DICER识别的双链RNA的形成，以及随后CBF1基因mRNA水平的下调。因此，CBF1-SVK调控回路不仅对于低温驯化这一已经有所认知的生物学功能非常重要，同时也为常温条件下植物生物量的积累提供了新的视野。本文的研究揭示了长链非编码RNA SVK-L在植物发育过程中的一种功能，同时也为天然反义转录本如何精确调控宿主基因mRNA稳定水平提供了一个分子机制解析。

** Peter Kindgren **