Project description:Prototypical micro RNAs (miRNAs) are 21~25-base-pair RNAs that regulate differentiation, carcinogenesis and pluripotency by eliminating mRNAs or blocking their translation, processes collectively termed RNA interference (RNAi). RNAi mediated by miRNAs regulates early development in zebrafish, and mouse embryos lacking the miRNA precursor processor, Dicer, are inviable. However, the role of miRNAs during mammalian fertilization is unknown. We here show using microarrays that miRNAs are present in mouse sperm structures that enter the oocyte at fertilization. Sperm contained a broad profile of miRNAs and a subset of potential mRNA targets were expressed in fertilizable, metaphase II (mII) oocytes. Oocytes contained transcripts for the RNAinduced silencing complex (RISC) catalytic subunit, EIF2C3 (formerly AGO3). However, levels of sperm-borne miRNA (measured by quantitative PCR) were apparently low relative to those of unfertilized, mII oocytes, and fertilization did not alter the part of the mII oocyte miRNA landscape that included the most abundant sperm-borne miRNAs. Coinjection of mII oocytes with sperm heads plus anti-miRNAs - to suppress miRNA function - did not perturb pronuclear activation or preimplantation development. Contrastingly, we provide evidence that nuclear transfer by microinjection alters the miRNA profile of enucleated oocytes. These data argue that sperm-borne prototypical miRNAs play a limited role, if any, in mammalian fertilization or early preimplantation development. Keywords: miRNA profiling Seven samples were analyzed for the study.
Project description:A greater understanding of the proteins involved in reproduction can benefit animal production. New advances in proteomics are having a major impact on our understanding of how spermatozoa acquire their capacity for fertilization [1]. Sperm proteomics aims at the identification of the proteins that compose the sperm cell and the study of their function [2]. The sperm cell is one of the most highly differentiated cells and is composed of a head with a highly compacted chromatin structure and a large flagellum with midpiece that contains the required machinery for movement and therefore to deliver the paternal genetic and epigenetic content to the oocyte [3]. By being so highly differentiated, spermatozoa are advantageous cells to study proteomics of specific compartments such as the membrane, which basically is the area of major importance for its role in interacting with the surroundings and the oocyte [4]. The fusion of a sperm and an oocyte is a sophisticated process that must be preceded by suitable changes in the sperm's membrane composition [5]. Recent studies of spermatozoa from the proteomic point of view have allowed the identification of different proteins in spermatozoa that are responsible for the regulation of normal/defective sperm functions [6]. While several techniques are available in proteomics, LC-MS based analysis of complex protein/peptide mixtures has turned out to be a mainstream analytical technique for quantitative proteomics [7]. Using this method, detailed proteomic data are now available for human [8], macaque [9,10], mouse [11], rat [12], bull [13-15], stallion [16], fruit fly [17], Caenorhabditis elegans [18], carp [19], rainbow trout [20], mussel [21], ram [22], honeybee [23] and rooster [24] sperm membrane proteins. Rabbit (Oryctolagus cuniculus) is an important mammalian species worldwide, being at the same time of commercial interest and a research model animal. European rabbit meat production is approximately 500 thousand tons, corresponding to a 30% share of world production [25]. Besides, rabbits account for the seventh highest number of animals slaughtered per year in the European Union-27, with 347,603 × 1000 head in 2014 [26]. In a previous work, we identified and quantified rabbit seminal plasma proteins between two different genotypes [27], concluding the clear effect of genotype in the abundance of certain seminal plasma proteins. However, it is unknown at present whether these differences also exist at sperm proteome level. Therefore, the aim of the present study was to characterise rabbit sperm membrane proteins through NanoLC-MS/MS analysis focusing on the influence of the genetic origin.
Project description:Prototypical micro RNAs (miRNAs) are 21~25-base-pair RNAs that regulate differentiation, carcinogenesis and pluripotency by eliminating mRNAs or blocking their translation, processes collectively termed RNA interference (RNAi). RNAi mediated by miRNAs regulates early development in zebrafish, and mouse embryos lacking the miRNA precursor processor, Dicer, are inviable. However, the role of miRNAs during mammalian fertilization is unknown. We here show using microarrays that miRNAs are present in mouse sperm structures that enter the oocyte at fertilization. Sperm contained a broad profile of miRNAs and a subset of potential mRNA targets were expressed in fertilizable, metaphase II (mII) oocytes. Oocytes contained transcripts for the RNAinduced silencing complex (RISC) catalytic subunit, EIF2C3 (formerly AGO3). However, levels of sperm-borne miRNA (measured by quantitative PCR) were apparently low relative to those of unfertilized, mII oocytes, and fertilization did not alter the part of the mII oocyte miRNA landscape that included the most abundant sperm-borne miRNAs. Coinjection of mII oocytes with sperm heads plus anti-miRNAs - to suppress miRNA function - did not perturb pronuclear activation or preimplantation development. Contrastingly, we provide evidence that nuclear transfer by microinjection alters the miRNA profile of enucleated oocytes. These data argue that sperm-borne prototypical miRNAs play a limited role, if any, in mammalian fertilization or early preimplantation development. Keywords: miRNA profiling
Project description:We performed mouse single oocyte RNA-seq and bulk oocyte CUT&Tag assays in the current project. In details, SMART-seq based single oocyte RNA-seq was performed at adult GV stage, GV3h stage and MII stage, using control and Dis3 oocyte-speicfic knockout (cKO) oocytes. RiboMinus-seq based single oocyte RNA-seq was performed at adult GV stage using control and Dis3 cKO oocytes, and at p20 GV stage using control, Dis3 cKO, Exosc10 cKO and Dis3/Exosc10 double cKO (dcKO) oocytes. Bulk CUT&Tag of anti-H3K27me3 was done in WT and Dis3 cKO oocytes at adult GV stage, and in WT and Dis3/Exosc10 dcKO oocytes at p20 stage. In addition, CUT&Tag of anti-RNA polymerase II (Ser2+Ser5) was performed in WT and Dis3 cKO oocytes at GV stage. All CUT&Tag experiments share the same rabbit-Igg negative control. All p20 stage oocytes were specified as p20. The non-specified GV oocytes were all adult GV oocytes.
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:Development of single cell sequencing allows detailing the transcriptome of individual oocytes. Here, we compare different RNA-seq datasets from single and pooled mouse oocytes and show higher reproducibility using single oocyte RNA-seq. We further demonstrate that UMI (unique molecular identifiers) based and other deduplication methods are limited in their ability to improve the precision of these datasets. Finally, for normalization of sample differences in cross-stage comparisons, we propose that external spike-in molecules are comparable to using the endogenous genes stably expressed during oocyte maturation. The ability to normalize data among single cells provides insight into the heterogeneity of mouse oocytes.
Project description:Purpose: Sperm-borne RNA are particularly sensitive to degradation and methodology-induced bias, thus necessitating the use of a consistent, effective RNA extraction protocol for inter-species comparisons. To this end, we established SpermBase, an RNA expression database consisting of small and large RNA expression data obtained using consistent methodologies. Methods: Total RNA was extracted from total sperm and sperm head samples using an RNA extraction protocol that required only slight, species-specific alterations at the lysis stage. Total RNA was subjected to either RNA-Seq (large RNA) or sncRNA-Seq (small RNA). Results: By using a consistent methodology, we were able to perform a cross-species analysis on the conserved features of large and small sperm-borne RNAs. We identified conserved features in both populations of RNAs in the four mammalian species (i.e., mouse, rabbit, rat, and human) surveyed. Conclusions: Our study demonstrates an effective, near-universal approach to the study of sperm-borne RNAs, and identifies conserved characteristics in the large and small RNA populations of mammalian sperm.
Project description:Parental dietary conditions can influence the metabolic traits of offspring. In mice, paternal consumption of low protein diet alters cholesterol and lipid metabolism of progeny. Here, we examine RNA species expressed in male reproductive tissues of mice. Protein restriction leads to altered levels of multiple small RNAs in mature sperm, as well as throughout the male reproductive tract, with decreased levels of let-7 family members and increased levels of 5â fragments of tRNA-Gly isoacceptors. Intriguingly, tRNA fragments are scarce in the testis, but their levels increase in sperm during post-testicular maturation in the epididymis. We find that epididymosomes â extracellular vesicles which fuse with sperm during epididymal transit â exhibit RNA payloads closely matching those of mature sperm, and can deliver tRNA fragments to immature sperm in vitro both in mouse and in bull. Finally, we show that tRNA-Gly-GCC fragments play a role in repressing genes associated with the endogenous retroelement MERVL, both in ES cells and in preimplantation embryos. Our results shed light on small RNA biogenesis during post-testicular sperm maturation, and link tRNA fragments to regulation of endogenous retroelements active in the early embryo. Zygotes were generated by ICSI from oocytes/females fed a Control diet and sperm/males fed either a Control or Low Protein diet. The sperm was isolated from either the Rete testis or the Cauda epididymis and injected either as a whole sperm or just the sperm head. Following fertilization by ICSI the zygotes developed for 28 hours (2C stage) and were harvested for single-embryo RNA-Seq.