P34CDC2 HOMOLOG IS LOCATED IN NUCLEOLI OF THE NERVOUS AND ENDOCRINE SYSTEMS

p34cdc2 protein kinase is a component of M phase-promoting factor (MPF), which plays an important role in controlling the mitotic and meiotic cell cycle. p34cdc2 contains a unique 16 amino acid sequence (PSTAIR) that is conserved from fission yeast to human. Using polyclonal anti-PSTAIR antibody, we detected the p34cdc2 homologue in the central nervous system of adult mice by western blotting. By immunohistochemical technique, we found that the p34cdc2 homologue was located in the nucleoli of neurons and glia in the central and peripheral nervous systems. In the central nervous system, positive cells were widely distributed from the cerebral cortex to the spinal cord. Immunoreactive cells were also detected in retina and pituitary. The evidence that the p34cdc2 is present in neurons which have lost the ability of cell division predicts another function of p34cdc2 family proteins besides the one that has generally recognized.