哺乳动物DNA拓扑异构酶IIβ在酵母中的独特亚核定位。

A distinct subnuclear localization of mammalian DNA topoisomerase IIbeta in yeast.

作者信息

Sakaguchi A, Akashi T, Kikuchi A

机构信息

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.

出版信息

Biochem Biophys Res Commun. 2001 May 18;283(4):876-82. doi: 10.1006/bbrc.2001.4856.

DOI:10.1006/bbrc.2001.4856

PMID:11350066

Abstract

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.

摘要

哺乳动物拓扑异构酶II的α和β亚型在其C端结构域（CTD）上存在差异，但这两种亚型都能弥补酵母top2突变。在本研究中，将哺乳动物拓扑异构酶IIα-CTD和IIβ-CTD用黄色荧光蛋白（YFP）标记，在酵母细胞中表达，并检测它们的定位。YFP标记的拓扑异构酶IIα-CTD均匀分布于整个细胞核，而YFP标记的拓扑异构酶IIβ-CTD则被隔离在一个核内亚区室中。缺失分析表明，拓扑异构酶IIβ-CTD的两个区域（氨基酸1207 - 1234和1513 - 1573）对于β亚型的特异性定位至关重要：如果去除这两个区域中的任何一个，突变的拓扑异构酶IIβ-CTD会均匀分布于整个细胞核。数据表明酵母细胞能够区分与这两种哺乳动物拓扑异构酶II亚型相关的核定位信号和核内亚定位信号。