Tissue-specific p53 expression in the nervous system.
P53 is a transcription factor that has been found to be expressed in association with cell proliferation and apoptosis. Previously, bacterial chloramphenicol acetyl transferase (CAT) enzymatic expression was predominantly found in the testes of p53 promoter driven-CAT transgenic mice. In the current study, we extended this study to survey p53 expression across both the central and peripheral nervous systems of the same strain of transgenic mice as well as their parental strain. High levels of p53 promoter driven-CAT activity was observed in the cerebellum, hippocampus, hypothalamus, pons, thalamus and upper cerebral spine. Furthermore, we consistently found unexpectedly high levels of p53 promoter-driven CAT expression in the eyes. These observations were reinforced by p53 protein analysis using a p53 pan ELISA assay. Immunohistochemical studies confirmed and further defined p53 expression in several regions of the nervous system. Significantly, p53 promoter-driven CAT expression was visualized in the Ammon horn of the hippocampus, in the Purkinje cells of the cerebellum and in the cornea as well as in the retina of the eye. Furthermore, strong p53 protein expression was found in the cornea of the parental mouse strain. p53 ELISA demonstrated a profile of p53 protein concentration, which correlate well with the high p53 promoter-driven CAT activities observed in the cerebellum, hindbrain, hypothalamus, thalamus, hippocampus, whole eyes as well as with the low CAT activities observed in the cortex and spinal cord. In both of these assays considerable p53 promoter activity and p53 protein levels were found in post-mitotic non-dividing cells.