Fgf8 transcripts are located in tendons during embryonic chick limb development

Fibroblast growth factor 8 (Fgf8) is a secreted growth factor involved in the initiation, outgrowth and patterning of vertebrate limbs (Genes Dev. 12 (1998) 1571). In this paper, we present a new site of expression of Fgf8 in the chick limb. Fgf8 transcripts are localised close to the muscle fibres, at the same level as the tendon-associated molecules, tenascin and scleraxis. Fgf8 is expressed in a sub-region of the tendons during limb development; its location being restricted to the area near the muscle. In addition, the restricted Fgf8 expression in the tendons allowed us to observe that the myogenic determination factor (MyoD) is not detected at the myotendinous junction.