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DNA topoisomerase I in the mouse central nervous system: Age and sex dependence
Author(s) -
Plaschkes Inbar,
Silverman F. William,
Priel Esther
Publication year - 2005
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20793
Subject(s) - biology , striatum , topoisomerase , cerebellum , central nervous system , senescence , hippocampus , cytoplasm , cerebral cortex , nuclear dna , hypothalamus , dna , microbiology and biotechnology , neuroscience , genetics , gene , dopamine , mitochondrial dna
Topoisomerase I (topo I) is a nuclear enzyme responsible for the topological state of DNA and therefore participates in most DNA transactions, particularly in transcription. Topo I, a ubiquitous enzyme, was identified and characterized in various cell types and tissues; however, the characterization of topo I in the intact central nervous system was not performed. Here we investigated, for the first time, the activity, level, and distribution pattern of topo I in the various selected brain regions in the mouse. In the visual cortex, cerebellum, and striatum the activity of topo I was 3–4‐fold higher compared to that found in the hippocampus and hypothalamus. Immunohistochemical and immunofluorescence analyses revealed specific distribution patterns of topo I protein in neurons of each of the areas examined. The highest topo I levels were observed in inhibitory neurons. In addition to the expected nuclear localization of this protein, some neurons exhibited significant cytoplasmic content as well. The activity and level of topo I is age‐ and gender‐dependent. It increases from birth to maturity and decreases, more significantly in males, with senescence. These results point to a possible importance and involvement of topo I activity and regulation in various brain functions. J. Comp. Neurol. 493:357–369, 2005. © 2005 Wiley‐Liss, Inc.