A POPULATION OF MYOGENIC CELLS DERIVED FROM THE MOUSE NEURAL-TUBE

Embryonic mouse neural tubes produce a variety of terminally different iated cells in vitro, mostly neurons and glia. We report here that som e of these cells differentiate into skeletal muscle cells. The possibi lity of mesoderm contamination was ruled out as follows. First, Dil(+) muscle cells were present in cultures from a Dil-labeled neuroepithel ium. Second, a small fraction of cultured neural tube cells coexpresse d muscle myosin and neuronal pill tubulin within the same cell. Third, embryos generated from embryonic stem cells in which nlacZ was target ed into the myogenic gene myf-5 expressed nlacZ in a localized region of the neural tube. These myf-5(+) cells coexpress neuronal and muscle markers in culture. The developmental significance of this phenomenon is discussed in the context of overlapping regulatory networks betwee n myogenesis and neurogenesis.