"Differentiation and Patterning of Vertebrate Tendons"
The functional integrity of the musculoskeletal system requires an elaborate and precise attachment of muscles to their respective skeletal elements. The collagen-rich muscle attachments range from narrow bands of dense connective tissue surrounding axial muscles to the long and complex limb tendons. In addition, the bones are interconnected by ligaments that span across joint regions, thereby securing the skeletal structure during joint movement. Despite their functional importance, surprisingly little is known about the genesis and patterning of tendons and ligaments. The goal of my research is to characterize and study the embryonic origin of these tissues, the signals that direct cells to assume the tendon cell fate and the subsequent signals regulating the exquisite patterning of the tendons and their interactions with their respective muscle and skeletal elements.
Historically, the lack of attention given to tendons and ligaments can largely be attributed to the absence of simple histological staining procedures or specific molecular markers for these tissues. We have recently found that Scleraxis, a bHLH transcription factor, is such a unique marker, expressed specifically and exclusively in tendons. Scleraxis expression is first detected in tendon progenitors, and the expression persists in the mature tendons. Based on these observation we developed genetic tools to support a broad research plan for studying tendon genesis and patterning. Most notable for this purpose are a mouse conditional mutant allele of Scleraxis, and a ScleraxisGFP transgenic mouse expressing the GFP protein specifically in tendons and ligaments.