Identification of Mitochondrial microRNAs Related to Egg Deterioration Caused By Post-Ovulatory Aging in Rainbow Trout

Mitochondria have recently been found to be associated with many miRNAs involved in various metabolic activities including programmed cell death. To identify molecular markers that can serve as indicators for rainbow trout egg quality, Solexa high throughput sequencing was used to profile miRNA expression in post ovulated eggs with different survival rates. Eleven mitochondrial-encoded miRNAs were identified, of which, two novel miRNAs, named omy-miR-nov874-3p and omy-miR-nov1316-5p, showed over10 times increased expression in low survival rate eggs as compared to high survival rate eggs. The results were further validated by RT-qPCR analysis. In total, 19 target genes of these two miRNAs were both predicted by PITA and miRanda algorithms, which are involved in immune response, ATP generation, Golgi function, as well as regulations of signaling, splicing, and transcriptional pathways.