Whole-genome DNA Methylation Profiling Of The Pineal Body Of Prepubertal And Pubertal Goats

To clarify the mechanism of mammalian puberty initiation is important to both regulating animal reproduction and reproductive health in human beings.Pulsive release of GnRH from hypothalamus plays a key role during the initiation of puberty.However,this pulsive release is strictly regulated by pineal body endocrine.Here,pineal glands from 3 pre-puberal and 3 puberal female Anhuai goats were subjected to whole-genome bisulfite sequencing(WGBS),and the sequencing results were performed GO(Gene Ontology)enrichment analysis and KEGG(kyoto Encyclopedia of Genes and Genomes)signal pathway analysis,aiming at screening those pineal body genes which were relative to puberty initiation and regulated by epigenetics.The results were as follows:(1)Prepuberty and puberty whole genome: among the total number of C bases in the C,CG,CHG,and CHH regions,methylated C accounted for 1.86%,35.73%,0.08% and 0.13% respectively in prepubertal goats and 1.93%,39.01%,0.08% and 0% respectively in pubertal goats.A total of 846 differentially methylated regions(DMR)were identified.Methylation levels in different functional regions of the genome,promoter,intron and 3'UTR were higher than those in the 5'UTR and exon;methylation density analysis showed a similar pattern.(2)In this study,we used GO enrichment analysis to find a number of molecular functional enrichment related to the biological functions of the study,including binding,protein binding,ion binding,hydrolase activity,calcium binding,kinase activity.The major biochemical metabolic pathways and signal transduction pathways of DMRs-related genes can be identified by significant enrichment;KEGG metabolic pathway analysis showed that the pathways related to reproductive endocrine were mainly GnRH signaling pathway?Oxytocin signaling pathway?Progesterone-mediated oocyte maturation?Estrogen signaling pathway?Ovarian steroidogenesis?GABAergic synapse?Oocyte meiosis?Prolactin signaling pathway.(3)Real-time fluorescence quantitative PCR was used to detect the genes related to enrichment pathway.Compared with the initial situation,only the two genes of HPSE and CAMK1 G were increased,which were related to steroid biosynthesis and oxytocin signaling pathway respectively.The expression of 8 genes was positively correlated with DNA methylation,and the expression of four genes was negatively correlated with DNA methylation,and these genes were found in the intron region of chromosome.Conclusion: Though there's no difference in the level of DNA methylation,there are many differences between DNA methylation patten between pre-puberal and puberal female goats' pineal genomes.These results suggested that the DNA methylation of pineal genome may involve in regulating the puberty initiation in female goat.