FC-16   SOX9, A HOMEOBOX GENE, IS EXPRESSED IN DEVELOPING SKIN AND BONE TISSUES OF THE RED DEER (‘CERVUS ELAPHUS’) ANTLER

NJ Croft, VA Randall The Department of Biomedical Sciences, University of Bradford, West Yorkshire, UK.

Sox9 is a Sry type homeobox gene sharing a strongly conserved 79 amino acid high mobility group box (HMG) domain. It has known expression in developing chondrocytes and teeth and also has a role in temperature sensitive sex determination in reptile species not possessing the Sry male sex determining gene. In human beings mutations in this gene result in congenital defects with genetic males possessing female phenotypes, as well as skeletal malformations described as campolmelic dysplasia. Mutations in Sox9 are fatal with offspring surviving only a few days after birth. In red deer (Cervus elaphus) antlers annually undergo rapid de novo development of new bone, skin and hair follicles under androgen control. We hypothesise that Sox9 is involved in the development of antler cartilage and osseous tissue and that it may also have a role in hair follicle development. Using RT-PCR we have identified Sox9 mRNA transcripts in all regions of the developing antler tip; this includes the epidermis and dermis, reserve mesenchyme and developing cartilaginous and osseous tissue. Positive control tissue (testes) showed strong expression of this gene as expected. Negative control (heart) tissue did not express Sox9. Results were confirmed in six different deer for the antler velvet epidermis and dermis; other tissues in at least two deer. In addition, expression was also identified in bald velvet showing only very early hair follicle bud developmental stages. The sequenced transcripts showed close similarity with the Bos taurus Sox9 gene. The findings in the developing antler tip suggest that Sox9 is involved in bone development with a predicted expression within the developing chondrocytes. In addition, we propose that Sox9 may also have a new and exciting role in the developing epidermis and hair follicles of the antler velvet.