Gene expression of proliferating cell nuclear antigen in rat brain

Proliferating cell nuclear antigen (PCNA), a non-histone nuclear protein which is preferentially present in rapidly growing cells, was found to express at a significant level in both cerebellum and cerebrum of adult rat brain. Analysis with in situ hybridization did not reveal any region in the brain which is particularly abundant in PCNA transcripts. However, it was noted that the cell bodies of Purkinje cells contained PCNA transcripts. The Purkinje cells are nerve cells of cerebellum and generally thought to be non-proliferative. Regardless the high level of PCNA mRNA in the rat brain, the PCNA protein was not detected in the tissue by immunostaining or immunoblotting analysis. This suggests that regulation of PCNA gene expression in brain may be at translational level.