To Build a Tongue

MDC Scientists gain new insights into Muscle Development in Embryos

What do the tongue, arm, and leg muscles have in common? They all evolve from wandering cells and two different genes steer their development. Elena Vasyutina and Prof. Carmen Birchmeier have published these new findings in mice and chicken embryos, in the journal Genes and Development* (www​.genes​dev​.org/​c​g​i​/​d​o​i​/​1​0​.​1​1​0​1​/​g​a​d​.​3​46205). Muscular precursor cells derive from the somite, a segmented structure which exists in vertebrates during embryogenesis. These precursor cells can unchain themselves from their neighbouring cells at a specific point in time and wander to a specific point in the connective tissue, where the muscle of the tongue and the muscles of the arms and legs normally develop. Two different genes in the muscle precursor cells control this process. One gene expresses the CXCR4 receptor, a molecule which recognizes a messenger molecule (chemokine), the second gene expresses what scientists call tyrosine kinase receptor c‑Met. Both genes act as chaperones of the wandering muscle precursor cells and ensure that such cells reach their destination, the result of which is normal muscle formation. Wandering processes during embryogenesis often resemble processes during cancer development. Indeed, both receptors, CXCR4 and met, play a role in the development of metastasis in breast and bowl cancer, two diseases that likewise exist of wandering cells.