Sox7 in vascular development: review, insights and potential mechanisms

Cardiovascular development is crucial to the survival of higher organisms, integrally transporting oxygen and nutrients and in later life, facilitating immune function. Only in recent years has the molecular basis of the formation of this ancient conduit system been explored. While transcription factors are essential to specify and differentiate core cellular and structural components of the developing heart and vessels, only a subset of these essential factors are currently known. A transcription factor of emerging importance in the cardiovascular system is Sox7, a member of the F group of Sox genes, as Sox7 removal in recent animal and cellular studies has resulted in disruptions of cardiovascular development. However, the molecular mechanisms of Sox7 action have largely remained obscure. In this paper, we first review the highly conserved and robust cardiovascular expression pattern of Sox7 across multiple species. We then provide evidence of a compelling role for Sox7 in vascular development, elucidating major pathways in which Sox7 functions, including VEGF/Flk1 signaling, Wnt signaling, and Notch pathway. Furthermore, we propose mechanisms connecting all of these important developmental pathways through Sox7, in a way not previously postulated in the developing vascular system. The emerging picture reveals Sox7 as an important developmental gene that connects other vascular regulators and that has significance in human disease.