成熟精子中RNA 的发现让科学家意识到精子不仅仅是运输父源DNA的载体，过去的研究已证实成熟精子所携带的一些miRNA能够影响早期胚胎发育及后代的性状。然而，目前尚不清楚成熟精子中是否还携带除miRNA之外其他种类的小RNA；对各种小RNA的生成及在成熟精子中的富集过程也知之甚少。
动物所段恩奎、韩春生和周琪三个实验室合作，从小鼠附睾尾分离得到高纯度的成熟精子，通过对其中的小分子RNA (18-40 nt) 深度测序结果分析，发现成熟精子中大量存在一类来源于tRNA的小分子RNA。这类小RNA的长度主要富集于29-34nt，类似但不同于睾丸中的piRNA；序列分析发现这类小RNA均来源于成熟tRNA的5’端序列。基于这类小RNA在成熟精子中的高富集性及其tRNA来源，将其命名为mse-tsRNAs (mature-sperm-enriched tRNA derived small RNAs)。mse-tsRNAs的含量占小鼠精子小RNA测序reads总量的67.54%；相比之下，精子中所有miRNA的总和仅占4.61%。mse-tsRNAs的表达量是从生精的晚期或离开睾丸（在附睾中）时开始迅速上升，提示这一时期存在特异的蛋白负责其剪切及富集。在成熟精子中，mse-tsRNAs 在精子头部富集，说明其能够在受精时进入卵细胞。
由于tRNA在进化上高度保守，tRNA来源的mse-tsRNAs 也在脊椎动物中呈高度保守，提示他们可能作为一种古老的父源信息在受精时传递给卵细胞。研究mse-tsRNA的生成/富集机制及其生物学功能将是下一步最为重要的工作。
该课题得到科技部、自然科学基金委和中国科学院的资助。文章于10月9日在Cell Research 杂志在线发表。（生物谷Bioon.com）
doi: 10.1038/cr.2012.141
PMC:
PMID:
A novel class of tRNA-derived small RNAs extremely enriched in mature mouse sperm
Hongying Peng, Junchao Shi, Ying Zhang, He Zhang, Shangying Liao, Wei Li, Li Lei, Chunsheng Han, Lina Ning, Yujing Cao, Qi Zhou, Qi Chen and Enkui Duan
The discovery of sperm-borne RNAs (mRNAs and small non-coding RNAs) has opened the possibility of additional paternal contributions aside from providing the DNA. It has been reported that the incoming sperm can provide information for its host egg cytoplasm, which functionally influences the order of cell division, possibly via delivering RNAs. Indeed, the sperm-borne miRNA and mRNA have been demonstrated as active players in early embryo development and transgenerational epigenetic inheritance. However, given the diversity of small RNA classes (miRNA, endo-siRNA, piRNA, etc.) generated during spermatogenesis, the contents and profiles of the small RNA population carried by mature sperm remain undefined. In the present study, we isolated mature sperm from the cauda epididymis of adult male mice. The purity of sperm was > 99% as evaluated by microscopy and was confirmed by RT-PCR analyses of different biomarkers . The RNA extracted from mature sperm, adult testis, and uterus were processed for small RNA (< 40 nt) deep sequencing
