Comparative analysis of differentially expressed genes in Sika deer antler at different stages.

Deer antlers serve as useful models of rapid growth and mineralization in mammals. During the period of rapid growth, the antlers of many species of deer will elongate by more than 2 cm per day, after which the antlers gradually ossify. However, little is known about the genes that are involved in their development, particularly the molecular mechanisms responsible for rapid growth and ossification. In our previous studies, we have reported on the transcriptome analysis of deer antlers at rapid growth and ossification stages. With the aim to get a comprehensive understanding of gene expression patterns during antler growth, in the present study, we performed a rigorous algorithm to identify differentially expressed genes between two different stages (60 and 90 days) during antler growth. A total of 16,905 significantly changed transcripts were identified. Those sequences were mapped to 5,573 genes with 2,217 genes up-regulated and 3,356 genes down-regulated (60 days vs. 90 days), including ribosomal proteins, translation initiation and elongation factors, transcription factors, signaling molecules and extracellular matrix proteins. We also performed the gene ontology (GO) functional enrichment and pathway enrichment analysis of gene expression patterns with hypergeometric test and Bonferroni Correction. Both the two stages were enriched with members of GO categories and distinct pathways. Our data represent the most comprehensive sequence resource available for the deer antler and provide a basis for further research on deer antler molecular genetics and functional genomics.