|ZHOU, YANG - Huazhong Agricultural University|
|Li, Congjun - Cj|
|Baldwin, Ransom - Randy|
|Schroeder, Steven - Steve|
|Rosen, Benjamin - Ben|
|YANG, LINGUO - Huazhong Agricultural University|
|Van Tassell, Curtis - Curt|
|Liu, Ge - George|
Submitted to: Gigascience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2018
Publication Date: 4/10/2018
Citation: Zhou, Y., Connor, E.E., Bickhart, D.M., Li, C., Baldwin, R.L., Schroeder, S.G., Rosen, B.D., Yang, L., Van Tassell, C.P., Liu, G. 2018. Comparative whole genome DNA methylation profiling of cattle sperm and somatic tissues reveals striking hypomethylated patterns in sperm. Gigascience. 7(5):1-13. https://doi.org/10.1093/gigascience/giy039.
Interpretive Summary: DNA methylation plays important roles in many processes like gene expression, genomic imprinting, repression of transposable elements, and gametogenesis. Using whole-genome bisulfite sequencing (WGBS), we profiled the DNA methylome of cattle sperms through comparison with three bovine somatic tissues (mammary grand, brain and blood). Our study provides a comprehensive resource for bovine sperm epigenomic research and enables new discoveries about DNA methylation and its role in male fertility. Farmers, scientist, and policy planners who need improve animal health and production based on genome-enable animal selection will benefit from this study.
Technical Abstract: Using whole-genome bisulfite sequencing (WGBS), we profiled the DNA methylome of cattle sperms through comparison with three bovine somatic tissues (mammary grand, brain and blood). Large differences between them were observed in the methylation patterns of global CpGs, pericentromeric satellites, partially methylated domains (PMDs), hypomethylated regions (HMRs) and common repeats. We detected selective hypomethylation of megabase domains of centromeric satellite clusters in sperms, which may be related with chromosome segregation during meiosis and their rapid transcriptional activation upon fertilization. We found more PMDs in the sperms than in the somatic tissues and identified sperm meiosis-related genes like KIF2B and REPIN1. Besides the common HMRs around gene promoters which showed substantial differences, the sperm-specific HMRs also targeted to distinct spermatogenesis-related genes, including BOLL, ASZ1, MAEL, PLD6, CTCFL, SYCP3, SYCE1, MND1, SPATA22, and DDX4. Although common repeats were heavily methylated, some hypomethylated repeats were enriched in gene promoters with large variations among tissues. For example, some young Bov-A2 repeats, which belong to the SINE family, were hypomethylated and could affect the promoter structures by introducing new regulatory elements. Our study provides a comprehensive resource for bovine sperm epigenomic research and enables new discoveries about DNA methylation and its role in male fertility.