Project description:Purpose: In order to understand the functional significance of sperm transcriptome in stallion fertility, the aim of this study was to generate a detailed body of knowledge about the sperm RNA profile that defines a normal fertile stallion. Methods: The 50 bp single-end ABI SOLiD raw reads were directly aligned with the horse reference sequence EcuCab2 using ABI aligner software (NovoalignCS version 1.00.09, novocraft.com) which uses multiple indexes in the reference genome, identifies candidate alignment locations for each primary read, and allows completion of the alignment. Results: Next generation sequencing (NGS) of total RNA from the sperm of two reproductively normal stallions generated about 70 million raw reads and more than 3 Gb of sequence per sample; over half of these aligned with the EcuCab2 reference genome. Altogether, 19,257 sequence tags with average coverage ?1 (normalized number of transcripts) were mapped in the horse genome. Conclusion: The sequence of stallion sperm transcriptome is an important foundation for the discovery of transcripts of known and novel genes, and non-coding RNAs, thus improving the annotation of the horse genome sequence draft and providing markers for evaluating stallion fertility. Reproductively fertile Stallion sperm transcriptome as revealed by RNA sequencing
Project description:Purpose: In order to understand the functional significance of sperm transcriptome in stallion fertility, the aim of this study was to generate a detailed body of knowledge about the sperm RNA profile that defines a normal fertile stallion. Methods: The 50 bp single-end ABI SOLiD raw reads were directly aligned with the horse reference sequence EcuCab2 using ABI aligner software (NovoalignCS version 1.00.09, novocraft.com) which uses multiple indexes in the reference genome, identifies candidate alignment locations for each primary read, and allows completion of the alignment. Results: Next generation sequencing (NGS) of total RNA from the sperm of two reproductively normal stallions generated about 70 million raw reads and more than 3 Gb of sequence per sample; over half of these aligned with the EcuCab2 reference genome. Altogether, 19,257 sequence tags with average coverage ≥1 (normalized number of transcripts) were mapped in the horse genome. Conclusion: The sequence of stallion sperm transcriptome is an important foundation for the discovery of transcripts of known and novel genes, and non-coding RNAs, thus improving the annotation of the horse genome sequence draft and providing markers for evaluating stallion fertility.
Project description:The discovery of RNAs (e.g. mRNAs, non-coding RNAs) in sperm has opened the possibility that sperm may function in delivering additional paternal information aside from solely providing the DNA1. Increasing evidence now suggests that sperm small non-coding RNAs (sncRNAs) can mediate intergenerational transmission of paternally acquired phenotypes, including mental stress2, 3 and metabolic disorders4-6. How sperm sncRNAs encode paternal information remains unclear, but the mechanism may involve RNA modifications. Here we show that deletion of a mouse tRNA methyltransferase, DNMT2, abolished sperm sncRNA-mediated transmission of high-fat diet (HFD)-induced metabolic disorders to offspring. Dnmt2 deletion prevented the elevation of RNA modifications (m5C, m2G) in sperm 30-40nt RNA fractions that are induced by HFD. Also, Dnmt2 deletion altered the sperm small RNA expression profile, including levels of tRNA-derived small RNAs (tsRNAs) and rRNA-derived small RNAs (rsRNA-28S), which might be essential in composing a sperm RNA ‘coding signature’ that is needed for paternal epigenetic memory. Finally, we show that Dnmt2-mediated m5C contributes to the secondary structure and biological properties of sncRNAs, implicating sperm RNA modifications as an additional layer of paternal hereditary information.
Project description:RNAs present in mature mammalian sperm are delivered to the zygote at fertilization, where they have the potential to affect early development. The biogenesis of the small RNA payload of mature sperm is therefore of great interest, as it may be a target of signaling pathways linking paternal conditions to offspring phenotype. Recent studies have suggested the surprising hypothesis that the small RNA payload carried by mature sperm may include RNAs that were not synthesized during testicular spermatogenesis, but that are instead delivered to sperm during the process of post-testicular maturation in the epididymis. To further test this hypothesis, we characterized small RNA dynamics during testicular and post-testicular germ cell maturation in mice, confirming and extending prior observations that testicular germ cell populations carry extremely low levels of tRNA fragments (tRFs), which only become highly abundant only after sperm have entered the epididymis. We examined the sperm RNA repertoire in greater detail, finding that the majority of 5’ tRNA fragments carry a 2’-3’ cyclic phosphate at their 3’ end, pointing to a role for RNaseA or T-family nucleases in tRNA cleavage in the male reproductive tract. The process of small RNA delivery to sperm can be recapitulated in vitro, as caput epididymosomes deliver small RNAs including tRFs and microRNAs to mature testicular spermatozoa. Finally, to definitively identify the tissue of origin for small RNAs in sperm, we carried out tissue-specific metabolic labeling of RNAs in intact mice, finding that mature sperm carry small RNAs that were originally synthesized in the somatic cells of the epididymis. Taken together, our data demonstrates that soma-germline small RNA transfer occurs in male mammals, most likely via vesicular transport from the epididymis to maturing sperm.
Project description:Increasing evidences indicate diet-induced metabolic disorder could be paternally inherited, but the exact sperm epigenetic carrier remains unclear. Here, in a paternal high-fat diet (HFD) mouse model, we revealed that a highly enriched subset of sperm small RNAs (30-34 nt) that derived from the 5â halves of tRNAs (tsRNAs), exhibit changes in both expression profiles and RNA modifications. Injection of sperm tsRNAs from HFD male but not synthetic tsRNAs lacking RNA modifications, into normal zygotes generated metabolic disorders in the F1 offspring. Injection of HFD sperm tsRNAs derails gene expression in both early embryos and islets of F1 offspring, enriched in metabolic pathways, but unrelated to DNA methylation at CpG-enriched region. Collectively, we uncover sperm tsRNAs as a type of âepigenetic carrierâ that mediate intergenerational inheritance of acquired traits. Mature sperm small-RNA profiles between High-fat-diet (HFD) and Normal-diet (ND) males; Transcriptional profiles of 8-cell embryos and balstocysts that developed from zygotes that injected with sperm RNAs from HFD vs ND males. Transcriptional profiles and RRBS profiles of islets of F1 offsrping that generated from zygotes that injected with sperm RNAs from HFD vs ND males.
Project description:In order to discover novel small RNAs expressed in mature sperm, we isolated mature sperm from mouse cauda epididymis, comparing with data from adult tesis and uterus. The small RNA fraction (18-40nt) was cloned and sequenced from total RNA of mature sperm, testis and uterus of mice.
Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study are to compare small non-coding RNA profiling (snRNA-seq) in WT oocyte, sperm and 2PN stage embryos to those sperm and 2PN stage embryos derived from WT, Dicer cKO and Drosha cKO. We further study the roles of sperm-borne small RNA on fertilization and pre-implantation embryonic development. Methods: Small RNA profiles of adult wild-type (WT) oocytes, adult WT sperm, 2PN stage embryos, adult Dicer cKO/Drosha cKO sperm, 2PN stage embryos were generated by deep sequencing in duplicate, using Ion Torrent Proton. The sequence reads that passed quality filters were analyzed at the small RNA level with two methods: Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. Results: Using an optimized data analysis workflow, we mapped about 30 million sequence reads per sample to the mouse genome (build mm9) and identified 16,014 small RNA (miRNA and endo-siRNA) in the oocyte, sperm and 2PN stage of WT and Dicer cKO/Drosha cKO mice with BWA workflow and 34,115 transcripts with TopHat workflow. Approximately 47% of the miRNAs showed differential expression between the WT and Dicer cKO sperm, ~52% of miRNAs were shown dysregulated in Drosha cKO sperm compared to those in WT sperm with a fold change ≥2.0 and p value <0.05. Data analysis with BWA and TopHat workflows revealed a significant overlap yet provided complementary insights in transcriptome profiling. Conclusions: Our study represents the first detailed analysis of small non-coding RNAs (miRNAs) in sperm and demonstrated that sperm-borne small RNAs are important for fertilization and early embrynic develoment, with biologic duplicates, generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of small RNAs profiles in mouse sperm, oocytes and 2PN stage of embryos. Our results show that NGS offers a comprehensive and more accurate quantitative and qualitative evaluation of small RNA contents within sperm or oocytes/embryos. We conclude that RNA-seq based small RNAs characterization in gametes would expedite genetic network analyses and permit the dissection of complex biologic functions during fertilization and embryonic development.
Project description:Sperm small RNAs are implicated in intergenerational transmission of paternal environmental effects. Small RNAs generated by cleavage of tRNAs, known as tRNA fragments (tRFs) or tRNA-derived RNAs (tDRs or tsRNAs), are an abundant class of RNAs in mature sperm, and can be modulated by environmental conditions. The biogenesis of tRFs in the male reproductive tract remains poorly understood. Angiogenin, a member of the Ribonuclease A superfamily (RNase A), cleaves tRNAs to generate tRFs in response to cellular stress. Four paralogs of Angiogenin, namely Rnase9, Rnase10, Rnase11, and Rnase12, are specifically expressed in the epididymis —a long, convoluted tubule where sperm mature and acquire fertility and motility. The biological functions of these genes remain largely unknown. Here, by generating mice deleted for all four genes (Rnase9-12-/-, termed “KO” for Knock Out), we report that these genes regulate fertility and small RNA levels. KO mice showed complete male sterility. KO sperm fertilized oocytes in vitro but failed to efficiently fertilize oocytes in vivo due to an inability of sperm to pass through the utero-tubular junction. Intriguingly, there were decreased levels of fragments of tRNAs (tRFs) and rRNAs (rRNA-derived small RNAs or rsRNAs) in the KO epididymis and epididymal luminal fluid. RNases 9-12 did not show ribonucleolytic activity in-vitro, suggesting that the changes in tRF and rsRNA levels are independent of enzymatic activity of these proteins. Importantly, KO sperm showed a dramatic decrease in the levels of tRFs, demonstrating a role of epididymis-specific Rnase9-12 genes in regulating sperm small RNA composition. Together, our results reveal an unexpected role of four epididymis-specific non-canonical RNase A family genes in regulating fertility and small RNA processing.
Project description:While mature sperm is transcriptionally inactive, recent studies show that, following testicular its exit, the mammalian sperm acquires a load of small non-coding RNAs during transit in the epididymis, the last stage of sperm maturation. Importantly, this non-coding RNA load is sensitive to environmental insults.
Project description:Sperm small RNAs have emerged as important non-genetic contributors to embryogenesis and offspring health. A subset of sperm small RNAs are thought to be acquired during epididymal transit. However, the transfer of RNAs from the somatic epididymis to the sperm has been questioned, and the identity of the specific small RNAs transferred remains unclear. Here, we employ Cre/Lox genetics to generate germline- and epididymal-specific Dgcr8 conditional knockout mice to investigate the dynamics of sperm microRNAs and their function in the early embryo. Interestingly, sperm from germline specific Dgcr8 knockout males restored the levels of 58 of the 98 (59%) miRNAs that were lost in testicular sperm during epididymal transit. Conversely, sperm from epididymal Dgcr8 knockouts displayed a 5-fold reduction in 25 miRNAs. This substantial loss of epididymal miRNAs in sperm was accompanied by transcriptomic changes in the embryo which was rescued by microinjection of epididymal miRNAs. These findings ultimately demonstrate the acquisition of miRNAs by sperm during epididymal transit and their regulation of post-fertilization embryonic gene expression.