A distinct subnuclear localization of mammalian DNA topoisomerase IIbeta in yeast.
Mammalian topoisomerase II isoforms alpha and beta are diverged in their C-terminal domain (CTD), but both isoforms complement the yeast top2 mutation. In this study, mammalian topoisomerase IIalpha-CTD and IIbeta-CTD were tagged with yellow fluorescent protein (YFP), expressed in yeast cells, and their localization was examined. YFP tagged-topoisomerase IIalpha-CTD was distributed evenly throughout the nucleus, while YFP tagged-topoisomerase IIbeta-CTD was sequestered into a subnuclear compartment. Deletion analysis revealed that two regions (amino acids 1207-1234 and 1513-1573) of the topoisomerase IIbeta-CTD are essential for specific localization of the beta isoform: if either of the two regions is removed, the mutant topoisomerase IIbeta-CTD distributes evenly throughout the nucleus. The data suggest that yeast cells distinguish the nuclear and subnuclear localization signals associated with these two mammalian topoisomerase II isoforms.
Sakaguchi
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Laboratory of Medical Mycology, Institute for Disease Mechanism and Control, University of Nagoya School and Faculty of Medicine, 65 Tsurumai-cho, Nagoya, Showa-ku, 466-8550, Japan.
Akashi
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T
Kikuchi
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A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology*; D017931:DNA Primers; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D004268:DNA-Binding Proteins; D004250:DNA Topoisomerases, Type II