BIOL303 Lecture Notes - Endochondral Ossification, Intramembranous Ossification, Lateral Plate Mesoderm
19 Dec 2013
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Document Summary
Intramembranous ossification involves the direct conversion of mesenchymal tissue into bone. Sclerotome leads to axial skeleton, including cell types such as chondrocytes and osteocytes. Chondrocytes and osteocytes would map to the same area as they are derived from the same population of sclerotome cells. Their differentiation is influenced by paracrine factors which lead to differential expression of transcription factors. Outline the spatial and regulatory relationships by which the sclerotome is specified. (include shh, fgf, pea3/erm, scleraxis, sox9, sox5/sox6 indicate the source of shh, the source of fgf, and the resulting tissues) Sclerotome will form the vertebrae as well as the syndetome. The syndetome then becomes tendon by expressing scleraxis. This specification is a direct result from fgf8 secreted by the myotome. Developing cartilage cells receive shh from the notochord which activates sox5/6 that repress scleraxis transcription. The intermediate mesoderm is able to become the kidney through interactions with the paraxial mesoderm.
