De novo characterization of the antler tip of Chinese Sika deer transcriptome and analysis of gene expression related to rapid growth.

Deer antlers are well known for their regeneration and rapid growth. However, little is known about the genes that are involved in their development, especially the molecular mechanisms responsible for rapid growth. In the present study, we produced more than 41 million sequencing reads using the Illumina sequencing platform. These reads were assembled into 89,001 unique sequences (mean size: 450 bp), representing more than 58 times as many Sika deer sequences previously available in the NCBI database (as of Sep 15, 2011). Based on a similarity search with known proteins, we identified 40,088 sequences with a cut-off E value of 10(-5). Assembled sequences were then annotated using Gene ontology terms, Clusters of Orthologous Groups classifications, and Kyoto Encyclopedia of Genes and Genomes pathways. In addition, we found a number of highly expressed genes involved in the regulation of Sika deer antler rapid growth, including transcription factors, signaling molecules, and extracellular matrix proteins. Our data represent the most comprehensive sequence resource available for the deer antler and provide a basis for new research on deer antler molecular genetics and functional genomics.