Expression of fas antigen in the normal mouse brain

The Fas antigen (Fas/Apo-1/CD95) is a cell surface receptor protein that mediates apoptosis-inducing signals and plays an important role in the immune system. In the central nervous system, during the period of naturally occurring cell death many neurons appear to die by apoptosis. We investigated the involvement of Fas in these events. The expression of Fas transcripts and protein was examined in the juvenile mouse brain. By RT-PCR analysis, Fas mRNA was detected in the cerebrum, cerebellum, and hippocampus of the brain. By immunohistochemistry, we found Fas in neurons localized in the CA2 and CA3 sectors of the hippocampus and in the cortical III layer of the cerebrum, but not neurons in the cerebellum. Furthermore, Fas was expressed on the primary cultured hippocampal and cerebral cells using immunofluorescence and flow cytometry. These results suggest that Fas is specifically expressed on neurons in the mouse brain during postnatal development.