C-MYC ANTIGENS IN THE MAMMALIAN ENTERIC NERVOUS-SYSTEM

We have investigated the presence of c-Myc-like antigens in the enteri c nervous system of the guinea-pig, rat, dog, sheep, monkey and human, c-Myc-like immunoreactivity was demonstrated by immunohistochemistry in the enteric nervous system of all animals tested, with one or more monoclonal antibodies raised against peptide sequences found in the hu man c-Myc protein. While in most cases the labelling was nuclear, cyto plasmic labelling was also observed. In the guinea-pig enteric nervous system, c-Myc-like immunoreactivity detected by two different antibod ies remained detectable for up to 4 h in the presence of cycloheximide . The size and density of labelled nuclei in the ileal submucous plexu s were consistent with exclusive neuronal labelling by one antibody an d neuronal plus glial labelling by the other. Double-labelling with an tiserum directed against vasoactive intestinal peptide revealed a subs et of c-Myc-immunoreactive neurons that also contain this neuropeptide . Anti-c-Mye antibodies specifically immunoprecipitated proteins from guinea-pig myenteric plexus-longitudinal muscle preparations whose siz es were consistent with previous observations for c-Myc antigens and w hose distribution was consistent with synthesis in the myenteric plexu s. We conclude that c-Myc proteins are expressed in mammalian enteric neurons and that they have characteristics similar to those of c-Myc p roteins in other nonproliferative cells.