Project description:Sperm cells are characterized by a unique epigenome, and an incorrect establishment of DNA methylation patterns during the differentiation of male germ cells into spermatozoa has been associated with male infertility in several species. While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bovine sperm is still scarce. The purpose of this study is to compare the methylomes of sperm and somatic cell types in cattle using the RRBS technology.
Project description:Sperm cells are characterized by a unique epigenome, and an incorrect establishment of DNA methylation patterns during the differentiation of male germ cells into spermatozoa has been associated with male infertility in several species. While bull semen is widely used in artificial insemination, the literature describing DNA methylation in bovine sperm is still scarce. The purpose of this study is to compare the methylomes of sperm and somatic cell types in cattle using the MeDIP-chip technology (methylated DNA immunoprecipitation followed by microarray hybridation).
Project description:Despite passing routine laboratory tests for semen quality, bulls used in artificial insemination (AI) can exhibit a significant variation in fertility. During fertility analysis, a subfertile bull with a low pregnancy rate of 10% was identified. To fully characterize the phenotype, a range of in vitro, in vivo and molecular assays were carried out. Additionally, knockout mice were generated to investigate the function of the identified mutated gene. Sperm from the subfertile bull exhibited reduced motility and severely reduced caffeine-induced hyperactivation compared to control bulls of proven fertility. Ability to penetrate the zona pellucida, cleavage rate, cleavage kinetics, and blastocyst yield after IVF or AI were significantly lower than in control bulls. Whole-genome sequencing and RNA sequencing of testis revealed a critical mutation in AK9 that affect splicing, shaping the majority of AK9 transcripts that leads to a premature termination codon and a severely truncated protein. Transgenic mice deficient in AK9 were generated, resulting in the production of immotile sperm that were unable to fertilize the oocyte. These sperm exhibited abnormalities, including a low ATP concentration. RNA-seq analysis of testis revealed differential gene expression of components of the axoneme and sperm flagella, as well as steroid metabolic processes. Sperm ultrastructural analysis showed a higher percentage of sperm with abnormal flagella. The infertility produced by AK9 mutant bull and in AK9 deficient mice indicates the essential metabolic role of AK9 in sperm motility and/or hyperactivation, which in turn affects sperm binding and penetration of the zona pellucida.
Project description:Turkey sperm lose viability within 8-18 h when stored as liquid semen using current methods and extenders. In contrast, turkey hens maintain viable, fertile sperm in their sperm storage tubules (SST) for 45 or more days following a single insemination. Our long-term objectives are to identify and characterize differentially expressed genes that may underlie this prolonged sperm storage and then use this information to develop improved methods for storing liquid turkey semen. We employed serial analysis of gene expression (SAGE) to compare gene expression patterns in turkey SST recovered from hens after artificial insemination (AI) with extended semen (sperm AI) or extender alone (control AI). We constructed two separate SAGE libraries with SST RNA obtained from sperm and control AI hens. We used these libraries to generate 95,325 ten-base pair SAGE tags. These 95,325 tags represented 27,430 unique genes. The sperm and control AI libraries contained 47,663 and 47,662 tags representing 18,030 and 19,101 putative unique transcripts, respectively. Approximately 1% of these putative unique genes were differentially expressed (P<0.05) between treatments. Tentative annotations were ascribed to the SAGE tag nucleotide sequences by comparing them against publicly available SAGE tag and cDNA sequence databases. Based on its SAGE tag nucleotide sequence, we cloned a partial turkey avidin cDNA and confirmed its up-regulation in the sperm AI SST. The bioinformatics and experimental procedures employed to clone turkey avidin and confirm its differential expression represent a useful paradigm for analyzing SAGE tag data from relatively uncharacterized model systems. Keywords: other
Project description:Prediction of male or semen fertility potential remains a persistent challenge that has yet to be fully resolved. This work analyzed several in vitro parameters and proteome of spermatozoa in bulls cataloged as high (HF; n=5) and low field (LF; n=5) fertility after more than a thousand artificial inseminations. Sperm motility was evaluated by Computer-Assisted Sperm Analysis. Sperm viability, mitochondrial membrane potential (MMP), and reactive oxygen species (mROS) of spermatozoa were assessed by flow cytometry. Proteome was evaluated by SWATH-MS procedure. Spermatozoa of HF bulls showed significantly higher total motility than the LF group (41.4% vs. 29.7%). Rates of healthy sperm (live, high MMP, and low mROS) for HF and LF bull groups were 49% and 43%, respectively (p > 0.05). Spermatozoa of HF bulls showed higher presence of differentially abundant proteins (DAPs) related to both energy production (COX7C), mainly OXPHOS pathway, and to the development of structures linked with the motility process (TPPP2, SSMEM1 and SPAG16). Furthermore, we observed that EQTN, together with other DAPs related to the interaction with the oocyte, were overrepresented in HF bull spermatozoa. The biological processes related to protein processing, catabolism, and protein folding were found to be overrepresented in LF bull sperm in which the HSP90AA1 chaperone was identified as the most DAP
Project description:Epigenetics (DNA methylation) profiling of sperm from Monozygotic (MZ) twin bull brothers comparing with each other Two-condition experiment, DNA methylation analysis of sperm from Monozygotic twin bull brothers which were hybridized as dye-swap in two-color arrays in a dye-balanced design.
Project description:Turkey sperm lose viability within 8-18 h when stored as liquid semen using current methods and extenders. In contrast, turkey hens maintain viable, fertile sperm in their sperm storage tubules (SST) for 45 or more days following a single insemination. Our long-term objectives are to identify and characterize differentially expressed genes that may underlie this prolonged sperm storage and then use this information to develop improved methods for storing liquid turkey semen. We employed serial analysis of gene expression (SAGE) to compare gene expression patterns in turkey SST recovered from hens after artificial insemination (AI) with extended semen (sperm AI) or extender alone (control AI). We constructed two separate SAGE libraries with SST RNA obtained from sperm and control AI hens. We used these libraries to generate 95,325 ten-base pair SAGE tags. These 95,325 tags represented 27,430 unique genes. The sperm and control AI libraries contained 47,663 and 47,662 tags representing 18,030 and 19,101 putative unique transcripts, respectively. Approximately 1% of these putative unique genes were differentially expressed (P<0.05) between treatments. Tentative annotations were ascribed to the SAGE tag nucleotide sequences by comparing them against publicly available SAGE tag and cDNA sequence databases. Based on its SAGE tag nucleotide sequence, we cloned a partial turkey avidin cDNA and confirmed its up-regulation in the sperm AI SST. The bioinformatics and experimental procedures employed to clone turkey avidin and confirm its differential expression represent a useful paradigm for analyzing SAGE tag data from relatively uncharacterized model systems. Keywords: other
Project description:IAP is one of the most transpositinally active retrotransposons in the mouse. Its transcription starts from the 5' long terminal repeat (LTR), and the expression level varied between cell types. This variation is thought to arise from differences in the epigenetic states, such as DNA methylation, of some copies of the 5' LTR between the cells. However, due to the high copy number and high sequence similarity, it was difficult to comprehensively and individually analyze epigenetic state of the IAP LTRs. Here, we developed a method called TEPBAT (Target Enrichment after Post-Bisulfite Adaptor Tagging) to analyze DNA methylation of individual retrotransposon copies. Using the method, we determined DNA methylation levels of >8,500 copies of genomic IAP LTRs (>97% of the copies targeted by the PCR primer) in sperm and tail. This revealed that the vast majority of the LTRs were heavily methylated both in sperm and tail, but hypomethylated copies were more frequently found in sperm than in tail. Interestingly, most of these hypomethylated LTRs were solo-type, belonged to specific subfamilies, and carried binding sites for transcription factors (TFs) active in male germ cells. We discuss possible roles for these TF-binding sites and the IAP internal sequence in regulation of LTR methylation.