Pantano Lorena, Jodar Meritxell, Bak Mads, Ballescà Josep Lluís, Tommerup Niels, Oliva Rafael, Vavouri Tanya
Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Can Ruti Campus, Badalona, Barcelona 08916, Spain.
Genetics Unit, Department of Physiological Sciences, University of Barcelona, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Biochemistry and Molecular Genetics Service, Hospital Clinic, 08036 Barcelona, Spain.
RNA. 2015 Jun;21(6):1085-95. doi: 10.1261/rna.046482.114. Epub 2015 Apr 22.
At the end of mammalian sperm development, sperm cells expel most of their cytoplasm and dispose of the majority of their RNA. Yet, hundreds of RNA molecules remain in mature sperm. The biological significance of the vast majority of these molecules is unclear. To better understand the processes that generate sperm small RNAs and what roles they may have, we sequenced and characterized the small RNA content of sperm samples from two human fertile individuals. We detected 182 microRNAs, some of which are highly abundant. The most abundant microRNA in sperm is miR-1246 with predicted targets among sperm-specific genes. The most abundant class of small noncoding RNAs in sperm are PIWI-interacting RNAs (piRNAs). Surprisingly, we found that human sperm cells contain piRNAs processed from pseudogenes. Clusters of piRNAs from human testes contain pseudogenes transcribed in the antisense strand and processed into small RNAs. Several human protein-coding genes contain antisense predicted targets of pseudogene-derived piRNAs in the male germline and these piRNAs are still found in mature sperm. Our study provides the most extensive data set and annotation of human sperm small RNAs to date and is a resource for further functional studies on the roles of sperm small RNAs. In addition, we propose that some of the pseudogene-derived human piRNAs may regulate expression of their parent gene in the male germline.
在哺乳动物精子发育末期，精子细胞会排出大部分细胞质并清除大部分RNA。然而，仍有数百个RNA分子留存于成熟精子中。这些分子中绝大多数的生物学意义尚不清楚。为了更好地理解产生精子小RNA的过程及其可能发挥的作用，我们对两名人类可育个体的精子样本中的小RNA含量进行了测序和表征。我们检测到了182种 microRNA，其中一些含量非常丰富。精子中最丰富的microRNA是miR-1246，其预测靶标存在于精子特异性基因中。精子中最丰富的一类小非编码RNA是PIWI相互作用RNA（piRNA）。令人惊讶的是，我们发现人类精子细胞含有从假基因加工而来的piRNA。来自人类睾丸的piRNA簇包含以反义链转录并加工成小RNA的假基因。在雄性生殖系中，几个人类蛋白质编码基因含有假基因衍生的piRNA的反义预测靶标，并且这些piRNA在成熟精子中仍然存在。我们的研究提供了迄今为止最广泛的人类精子小RNA数据集和注释，是进一步研究精子小RNA作用的功能研究的资源。此外，我们提出一些假基因衍生的人类piRNA可能在雄性生殖系中调节其亲本基因的表达。
