The testis transcriptome is highly complex and includes RNAs that potentially hybridize to form double-stranded RNA (dsRNA). We isolated dsRNA using the monoclonal J2 antibody and deep-sequenced the enriched samples from testes of juvenile Dicer1 knockout mice, age-matched controls, and adult animals. Comparison of our data set with recently published data from mouse liver revealed that the dsRNA transcriptome in testis is markedly different from liver: In testis, dsRNA-forming transcripts derive from mRNAs including promoters and immediate downstream regions, whereas in somatic cells they originate more often from introns and intergenic transcription. The genes that generate dsRNA are significantly expressed in isolated male germ cells with particular enrichment in pachytene spermatocytes. dsRNA formation is lower on the sex (X and Y) chromosomes. The dsRNA transcriptome is significantly less complex in juvenile mice as compared to adult controls and, possibly as a consequence, the knockout of Dicer1 has only a minor effect on the total number of transcript peaks associated with dsRNA. The comparison between dsRNA-associated genes in testis and liver with a reported set of genes that produce endogenous siRNAs reveals a significant overlap in testis but not in liver. Testis dsRNAs also significantly associate with natural antisense genes—again, this feature is not observed in liver. These findings point to a testis-specific mechanism involving natural antisense transcripts and the formation of dsRNAs that feed into the RNA interference pathway, possibly to mitigate the mutagenic impacts of recombination and transposon mobilization.

中文翻译：

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睾丸中双链 RNA 的广泛形成

睾丸转录组非常复杂，包含可能杂交形成双链 RNA (dsRNA) 的 RNA。我们使用单克隆 J2 抗体分离了 dsRNA，并对来自幼年Dicer1敲除小鼠、年龄匹配的对照和成年动物的睾丸的富集样本进行了深度测序。我们的数据集与最近发表的小鼠肝脏数据的比较表明，睾丸中的 dsRNA 转录组与肝脏明显不同：在睾丸中，形成 dsRNA 的转录物源自包括启动子和直接下游区域的 mRNA，而在体细胞中，它们更常见来自内含子和基因间转录。产生 dsRNA 的基因在分离的雄性生殖细胞中显着表达，在粗线期精母细胞中特别富集。性（X 和 Y）染色体上的 dsRNA 形成较低。与成年小鼠相比，幼年小鼠的 dsRNA 转录组复杂程度明显较低，因此 Dicer1 敲除对dsRNA 相关转录本峰总数的影响可能很小。将睾丸和肝脏中的 dsRNA 相关基因与已报道的一组产生内源 siRNA 的基因进行比较，发现睾丸中存在显着重叠，但肝脏中则不然。睾丸 dsRNA 还与天然反义基因显着相关——同样，在肝脏中没有观察到这一特征。这些发现指出了睾丸特异性机制，涉及天然反义转录物和进入 RNA 干扰途径的 dsRNA 的形成，可能减轻重组和转座子动员的诱变影响。