SCHWEITZER, R.: Cell Fate Determination and Patterning of Vertebrate Tendons

Surprisingly little in known about the differentiation on patterning of vertebrate tendons, largely due to the absence of a good molecular marker for this tissue. We have recently demonstrated that Scleraxis, a bHLH transcription factor, is a specific marker for tendons. Scleraxis is expressed in tendon progenitors and the expression persists in differentiating tendons and in the fully formed tendons of the adult animal. Using Scleraxis as a marker, we have identified the signals required to induce the limb tendon progenitors. The progenitor cell population is induced by an ectodermal signal(s) and restricted by BMP signaling in the early limb bud mesenchyme.Generation of a conditional mutant mouse for Scleraxis and of transgenic mice with expression directed to the tendon tissue will also be discussed.