2022.10.24 胚珠中的24-nt sRNA调控种子发育

The Plant Cell 的In brief系列文章真的是学写作很好的素材，在保留原文章核心内容的同时简单易懂，结构完整，本次截取In brief中的一段。

原文章：

Burgess, Diane, Hiu Tung Chow, Jeffrey W Grover, Michael Freeling, and Rebecca A Mosher. ‘Ovule SiRNAs Methylate Protein-Coding Genes in Trans’.The Plant Cell34, no. 10 (27 September 2022): 3647–64.https://doi.org/10.1093/plcell/koac197.

In brief:

Lopez-Gomollon, Sara. ‘Keep Calm and Methylate on: Ovule Small RNAs Methylate Protein-Coding Genes in Trans Related with Fertility’.The Plant Cell34, no. 10 (27 September 2022): 3491–92.https://doi.org/10.1093/plcell/koac224.

中文:

在新的工作中，作者探究了拟南芥亲缘植物Brassica rapa（芫菁？）胚珠中24-nt的sRNA。与拟南芥不同且非常有趣的是，在芫菁中失去参与24-ntsRNA合成的蛋白可导致高比例的种子败育。使用sRNA-seq, RNA-seq和DNA甲基化分析，作者发现胚珠中sRNA合成与其他组织中非常不同。在叶子中大多数的24-nt的sRNA来源于转座因子，而在胚珠中这些24-nt的sRNA主要来源于转座子很少（transposon-free regions）的被称为siren loci的区域。这些小RNA的产生与假定的染色质重塑因子CLSY3和PoIIV亚族NRPD1两个拷贝的其中之一相关。siren loci有可能与转座子重叠，但大部分24-nt sRNA产生于临近的无转座子区域，并且可以顺式触发甲基化，说明它们的主要功能并不是沉默转座子。

一项更早的研究表明24-nt sRNA可以靶向与其错配小于2的蛋白编码基因，介导其甲基化并触发转录沉默。

In brief原文：

In the new work, the authors explore the 24-nt sRNA population in ovules of Brassica rapa, a relative of Arobidopsis. Brassica rapa is especially interesting to syudy because, unlike Arabidopsis, the loss of the proteins involved in the production of 24-nt sRNA results in a high rate of seed abortion. Using sRNA-seq, RNA-seq and DNA methylation analyses, the authors found that the population of 24-nt sRNA is quite different in ovules compared to other tissues. While in leaves most 24-nt sRNA come from transposon elements, in ovules these 24-nt sRNA are mainly produced from transposon-free regions called siren loci. Their production is associated with the putative chromatin remodeler CLSY3 and one of the two copies of POIIV subunit NRPD1. Siren loci may overlap with transposons, but most of the 24-nt sRNA are produced from adjacent transposon-free regions and trigger methylation in cis, suggesting that their primary role is not transposon silencing.

An earlier study showed that 24-sRNA can trigger DNA methylation and transcriptional silencing with up to 2 mismatches between sRNA and target coding gene.

这段主要讲述了为什么要选择芫菁做研究对象和重点结果，为了结果的完整性，我结合加了原文（不是In brief）一句话补充sRNA的具体功能。这段对实验背景、方法、重点结果、结论都做了高度概括，逻辑清晰重点突出。

比较好的动词：

trigger

文中多be动词，没有太多很精彩的动词，但胜在逻辑很好。

1.简单介绍背景（The 24-nt sRNA is crucial for seed development in Brassica rapa，这是本项研究的重要基础）；

2.从一般（其他组织中情况）到特殊（胚珠中情况）；

3.对特殊的解析和得出结论