Transcriptome Sequencing And Differentially Expressed Genes Screening Of Postpartum Placenta In Dairy Goats

Improving the breeding performance of dairy goats is of great value to increase the total milk yield of dairy goats and the economic benefit of dairy goats.As the link between the mother and the fetus,the degree of differentiation,depth of implantation,congestion and oxygenation of the placenta will affect the viability and health status of the fetus.It is the key to ensure the reproductive performance of ewe.In this study,the postpartum placenta of dairy goats was used as the test material to analyze the relationship between the placental traits of dairy goats with different littering numbers and different parities and the lambing performance of dairy goats.The placental tissues of 9 dairy goats with different litter size of the same parity were sequenced by RNAseq technology to screen out the key genes that may affect the reproductive performance.Two key candidate genes were cloned by PCR and bioinformatics analysis was carried out.The effect of key candidate genes on the invasion and migration of trophoblast cells(GTCs)in the placental trophoblast cells of milk goat was studied through overexpression and interference,and the mechanism of the influence of key candidate genes on the invasion and migration of trophoblast cells(GTCs)in the endometrium and the construction of maternal-fetal connection to ensure multiple pregnancy was preliminarily explored.The main results are as follows:1.The placental quality,placental efficiency,total number of cotyledons,cotyledon carrying efficiency,and total cotyledon area of dairy goats after childbirth increased significantly with the increase in litter size;littering and placental efficiency,cotyledon carrying efficiency,total number of cotyledons,placental mass and total cotyledon The area has a very significant positive correlation.2.A total of 148 common differential genes were detected in placental tissues of different litters.The differential genes are mainly enriched in biological processes such as cell growth regulation,cell adhesion and bioadhesion,as well as cell adhesion molecule pathways and neuroactive ligand-receptors interactive signaling pathway;Seven key candidate genes(CDH1,PRP6,SDC2,CALCRL,F2 R,P2RY14 and EDNRB)were screened out.The expression of CDH1 gene was down-regulated in the placenta tissue of multiple lambs,which played a role in trophoblast differentiation and blastocyst morphogenesis and established effective nutrition and nutrition.The oxygen transport platform is very important.The expression of PRP6 gene is up-regulated in the placenta tissue of multiple lambs,and it plays a key role in coordinating other hormones to stimulate trophoblast cells and fetal development.3.The CDS regions of CDH1 and PRP6 genes from dairy goats were 2652 bp and 720 bp,encoding 883 and 239 amino acids,respectively,which were highly homologous with Goat(Capra Hircus,XM 005692180.3)、cattle(Bos Taurus,AY508164.1)and sheep(Ovis Aries,XM＿0279781181).4.The over-expression vectors pcDNA3.1-CDH1 and pcDNA3.1-PRP6 were successfully constructed,and their mRNA expression levels were up-regulated by 35-fold and 70-fold,respectively;After overexpression of CDH1 gene,the average migration ability of GTCs decreased significantly by 36.21%,the expression of CCND2,MYC and IGF2 were decreased,the expression of MMP-2 was significantly inhibited,and the expression of E-cadherin was promoted;After interference with CDH1 gene,the average migration capacity of GTCs is significantly increased by 55.83%,the expressions of CCND2,MYC and IGF2 were upregulated,the expression of MMP-2 was significantly promoted,and the expression of Ecadherin was inhibited;After overexpression of PRP6 gene,the average migration ability of GTCs increased significantly by 40.83%,the expression of CCND2,MYC and IGF2 increased,significantly promoted the expression of MMP-2,and inhibited the expression of E-cadherin;After the interference of PRP6 gene,the average migration ability of GTCs significantly decreased by 32.48%,the expression of CCND2,MYC and IGF2 were down-regulated,the expression of MMP-2 was significantly inhibited,and the expression of E-cadherin was promoted.It shows that CDH1 and PRP6 genes are involved in the migration and invasion of placental trophoblast cells during pregnancy,and affect the establishment of maternal-fetal connection and the survival and development of lambs.In summary,the CDH1 and PRP6 genes selected by the transcriptome sequencing of postpartum placental tissue in dairy goats are the key genes that regulate normal pregnancy and ensure fetal growth and development during pregnancy,and affect the migration and invasion of placental trophoblast cells at different lambing levels.It is very important in the process of embryo attachment to ensure the placental differentiation,the depth of placental implantation,placental hyperemia and oxygenation,which will affect the maternal lambing performance.This research lays a theoretical foundation for the in-depth study of the reproductive performance of dairy goats and the improvement of lambing rate.