AUTOANTIGEN KU IN THE BRAIN - DEVELOPMENTALLY-REGULATED EXPRESSION AND SUBCELLULAR-LOCALIZATION

A double-stranded DNA end-binding factor with high levels of expressio n in brain and testis of adult mice was identified as the Ku protein, earlier described as an autoantigen in connective tissue diseases and found to be essential for recombination of the immunoglobulin genes an d DNA repair. High Ku levels were found in the cerebellum and pituitar y gland, lower levels in the hippocampus, hypothalamus and white matte r structures. Ku levels were much higher in embryonic rat brain than i n the adult brain, suggesting a role of the Ku protein in brain develo pment. In embryonic rat brain, Ku was associated with cell nuclei, but was predominantly located in the cytosol in the adult rat cerebellum and hippocampus. The abundant expression of Ku in the brain suggests t he involvement of Ku autoantibodies in the pathogenesis of neuropsychi atric complications in connective tissue diseases. (C) 1998 Rapid Scie nce Ltd.