MicroRNA expression and regulation in mink uterus during embryo implantation. Neogale vison breed:American mink

Perinatal losses occur in all gestational mink, the causes and the mechanisms of embryonic motality remain unclear. MicroRNA (miRNA) are small non-coding RNAs, which are involved in the regulation of gene expression at the posttranscriptional level. Several genes in mink uterus have been identifed regulate embryo development, However, very limited information exists on the miRNA expression during embryo implantation. Here, we analyzed miRNAome of the uterus in implantation sites (IMs) and inter-implantation sites (inter-IMs) in mink by Illumina sequencing. The results showed that 3738 known microRNAs and 232 potential novel miRNAs were identified. 44 differentially expressed known microRNAs, 6 miRNAs were upregulated and 38 miRNA (log2 Ratio >2) were downregulated at the IMs compared with inter-IMs, that putatively regulate the expression of 264884 genes, Of these predicted targets, 843 were also differentially expressed in IMs with inter-IMs as determined by RNA-Seq. The pathway analysis revealed that the predicted targets were involved in several pathways, such as cell adhesion, immune system process, extracellar matrix, protein binding and signal transduction. The present study for the first time explores key regulatory roles of miRNAs in mink endometrium during the implantation and placentation, our findings indicate a possible prospective use of miRNA as biomarkers for pregnancy success.