miR-16 Regulates Chicken Growth via Targeting FOXO1A and ACVR2A

MiRNAs are known to be involved in growth and metabolism process. This study aims to identify candidate miRNA for chicken growth. MiRNA array and small RNA sequencing revealed that miR-16 showed significantly lower expression in the skeletal muscle tissues of fast-growing chickens compared with that of slow-growing ones. We herein found a 54 bp indel mutation in the forward of miR-16 precursor among many populations, including Chinese domestic and imported breeds through directly sequencing. Further association analysis in a F₂ resource population showed that this indel was significantly associated with chicken growth traits. Body weight during 28 days to 84 days for Ins/Ins birds was significantly (P < 0.05) greater than for Del/Del birds. Interestingly, over expressing pri-miR-16 vector including the 54-bp insertion segment in DF-1 cell induced lower miR-16 expression compared to the deletion type, and two abnormal splicing modes were merely found in insertion types, which may decrease the generation of mature miR-16. In vitro, over expression of miR-16 could inhibit the proliferation of DF-1 and skeletal muscle cells. Further study proved that miR-16 could identically down-regulate two severe growth related genes (FOXO1A and ACVR2A) by directly targeting their 3’UTR. These data suggest that miR-16, mediated by a 54-bp indel in the primary RNA, has important function on avian growth traits. However, more systemic investigations are needed to elucidate the regulatory mechanism of miR-16 in the muscle growth process in future.