MicroRNAs-wide analysis of primordial germ and somatic cells reveals sexual and developmental differential functional regulation in mouse embryonic gonads

We have characterized by small-RNAseq the miRNA expression pattern of mouse male and female Primordial Germ Cells (PGCs) and somatic stromal cells from gonads at E11.5, E12.5 and E13.5. MiRNA accumulation was higher in somatic cells than in PGCs and more stable across the different developmental stages analyzed. Differential expression analyses showed differences in the regulation of key miRNA clusters such as miR-199-214, miR-182-183-96 and miR-34c-5p whose targets have defined roles in both germ and somatic cells in gonadal sexual determination. Extensive analyses of miRNA sequences revealed an increase in non-canonical isoforms in PGCs at E12.5 compared to E11.5 and E13.5 and a dramatic change in isomiR expression and non-template 3' nucleotide additions in female PGCs at E13.5 respect to the other samples. Overall design: miRNA profiles of 12 different mice samples, corresponding to PGCs and gonadal somatic cells from E11.5, E12.5 and E13.5 male and female gonads, generated by deep sequencing using MiSeq Sequencing System (Illumina).