Full-length transcriptome and microRNA sequencing reveal the specific gene-regulation network of velvet antler in sika deer with extremely different velvet antler weight.

Velvet antler displays the fastest and most robust tissue proliferation in the animal world, it is a model for a complete organ development/regeneration, and alternative medicine, tonic made from velvet antler, was beneficial for human. The weight of velvet antler had high biomedical and economic value, but the related regulation mechanisms controlling velvet antler weight remain unclear. In this study, extremely heavy and light velvet antler groups were selected from a sika deer population of 100 individuals with extreme velvet antler weight. A combination of full-length transcriptome sequencing and microRNA sequencing to the proliferation zone in the tip of velvet antler was applied. A total of 55306 transcripts and 1082 microRNAs were identified. Some highly expressed genes (COL1A1, COL1A2, COL3A1, FN1, and ATP6) and microRNAs (miR-21, let-7i, and miR-27b) were highly correlated with the physiological and growth characteristics of velvet antlers. Among the 334 differentially expressed genes, we found that most of the genes were located in the developmental process, especially animal organ development process. It is exciting to see that more blood vessels were found in the growing tip of heavy velvet antler through histological observation, and GO term of blood vessel development was also significant different between two groups. The combination analysis with mRNA and microRNA data in velvet antler showed a specific regulation network involved in the development of bone, mesenchyme, cartilage, and blood vessel, and helped us clearly find out the candidate 14 genes and 6 microRNAs, which could be used for selecting significant DNA markers of velvet antler weight.