Our research focuses on the control of T cell development in the thymus. The specialized environment of the thymus is essential for efficient production of functional non-self reactive T cells. We aim to understand the way in which signals from the thymic epithelium direct the differentiation of developing T-lineage cells. Currently we are investigating the role of morphogens secreted by the thymic epithelium (Sonic hedgehog (Shh), and Bone morphogenetic protein(BMP)4, in particular) in T cell development. Classical morphogens are secreted signalling molecules that specify cell fate and patterning during embryonic development by providing concentration-dependent positional information. Our work has demonstrated that Shh and BMP4, powerful regulators of embryonic development of many mammalian tissues, also function in the control of self-renewing tissues in the adult, such as the immune system. We showed that Shh and BMP4 are involved in the control of differentiation at multiple stages of T cell development and they now aim to define the molecular events that underlie their functions.