韩国延世大学的Seong Wook Yang和Seok Keun Cho课题组在Molecular Plant发表了一篇题为Light triggers the miRNA-biogenetic inconsistency for de-etiolated seedling survivability in Arabidopsis thaliana的研究论文，文章解析了miRNA生物发生的不一致性对于去黄化幼苗的生存及其对不断变化光照条件的适应性具有重要意义。

暗生长的幼苗转向光中会引起巨大的转录组变化，并伴随着生长发育的转变。本文中，作者发现microRNA（miRNA）的生物发生在去黄化过程中也经历着调控变化。黄化幼苗保持较低水平的初级miRNAs(pri-miRNAs)和miRNA加工核心蛋白，如Dizer-like 1(DCL1)、serrate(SE)和HYPONASTIC Leave1(HYL1)，而在去黄化过程中pri-miRNAs和加工组分都积累到较高水平。然而，大多数miRNAs的水平在光照下并没有显著增加。为了协调这种不一致性，作者证明可能存在一个未知的抑制因子降低了miRNA的加工活性，而光诱导的SDN1(SMALL RNA DEGRADING NUCLEASE 1)缩短了去黄化幼苗中多个miRNA的半衰期。

综上所述，这些数据表明了一种新的机制，miRNA生物发生具有不一致性，这解释了miRNA生物发生在脱黄化过程中的复杂性。这一机制对经历长期暗形态后去黄化幼苗的生存及其对不断变化光照条件的适应性至关重要。

miRNA 生物发生不一致性的图形摘要

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ABSTRACT

The shift of dark-grown seedlings into light causes enormous transcriptome changes followed by a dramatic developmental transition. Here, we show that microRNA (miRNA) biogenesis also undergoes regulatory changes during de-etiolation. Etiolated seedlings maintain low levels of primary miRNAs (pri-miRNAs) and miRNA processing core proteins, such as Dicer-like 1, SERRATE, and HYPONASTIC LEAVES 1, whereas during de-etiolation both pri-miRNAs and the processing components accumulate to high levels. However, the levels of most miRNAs do not notably increase in response to light. To reconcile this inconsistency, we demonstrated that an unknown suppressor decreases miRNA-processing activity and light-induced SMALL RNA DEGRADING NUCLEASE 1 shortens the half-life of several miRNAs in de-etiolated seedlings. Taken together, these data suggest a novel mechanism, miRNA-biogenetic inconsistency, which accounts for the intricacy of miRNA biogenesis during de-etiolation. This mechanism is essential for the survival of de-etiolated seedlings after long-term skotomorphogenesis and their optimal adaptation to ever-changing light conditions.

文章链接：https://doi.org/10.1016/j.molp.2019.10.011