Identification of a specific 13-miRNA expression signature during follicle activation in Zebrafish. Danio rerio

Purpose: We aimed to investigate important miRNA events and to define specific miRNA expression signature underlying the follicle activation of zebrafish. Methods: By using small and regular RNA-sequencing, we performed transcriptomic analyses of PG (primary growth stage I; inactive) and PV (pre-vitellogenic stage II; activated) follicles to decipher important miRNA and gene events underlying follicle activation of zebrafish. We identified differentially expressed miRNAs for subsequent qPCR validation and miRNA::target gene prediction. Interaction of candidate miRNA:: target gene pairs were further validated by luciferase reporter assay. Global gene networks involved during PG-to-PV transition were also assessed by Gene Ontology as well as KEGG pathway analyses. Results and Conclusion: Our expression results indicated that PG follicles can be well differentiated from PV follicles by simply using a specific 13-miRNA expression signature (let-7a, -7b, -7c-5p, -7d-5p, -7h, -7i; miR-21, -23a, -27c-3p, -107a-3p, -125b-5p, -145-3p, -202-5p). Besides, we validated interactions of let-7i::atg4a, miR-202-5p::c23h20orf24 and miR-144::ybx1 by luciferase reporter assay. Purpose: we aimed to investigate important miRNA events and to define specific miRNA expression signature underlying the follicle activation of zebrafish Overall design: To identify differentially expressed miRNAs and its potential downstream targets during follicle activation of zebrafish, we carried out transcriptomic profiling by both small and regular RNA-sequencing. By intersecting gene lists of the online predicted targets and RNA-seq derived differentially expressed transcripts with a reciprocal expression pattern of miRNAs, we shortlisted 6 pairs of miRNA::target gene for validation using luciferase reporter assay.