GAP43 identifies developing muscle cells in human embryos.

GAP43 has long been regarded as a neurone specific molecule present intraneuronally in both the central and peripheral nervous system, especially during development and regeneration. GAP43 has, however, recently been demonstrated in developing muscle cells of the chicken. In the prsent investigation, we have used immunohistochemistry to investigate whether GAP43 is also expressed in developing human muscle cell. Using specific monoclonal antibodies as markers for developing muscle cells (desmin) and axon terminals (synaptophysin), our results show that GAP43 is expressed in aneural, human embryonic muscle cells.