Analysis of age dependent changes of Topoisomerase II α and β in rat brain

Abstract

Eukaryotic Topoisomerase II (Topo II) is present in two isoforms α and β. The α isoform is predominantly localized in proliferative tissue, while β isoform is present in all tissues. In the present study we report the activity and protein levels of Topoisomerase II α and β in rat brains of different age groups viz.: E11 (Embryo day 11), E18 (Embryo day 18), post-natal day 1, young ( < 10 days), adult ( < 6 months) and old ( > 2 years). Topoisomerase II β isoform is found to be the predominant form in brain tissue but Topoisomerase II α is found in embryos up to post-natal day 1. The studies to examine the regional distribution of Topoisomerase II β in brain showed highest activity in cerebellar region and that too only neuronal cell fraction. There was a significant age-dependent decline in this activity. Hence, Topoisomerase II β may have some unknown function in cerebellum and the low levels of Topoisomerase II β activity in ageing cerebellum may contribute to the genomic instability in cerebellar region of ageing brain. © 2003 ISDN. Published by Elsevier Ltd. All rights reserved.