粟酒裂殖酵母Mcm2/Cdc19p的核定位需要MCM复合体组装。
Nuclear localization of Schizosaccharomyces pombe Mcm2/Cdc19p requires MCM complex assembly.
作者信息
Pasion S G, Forsburg S L
机构信息
The Salk Institute for Biological Studies, Molecular Biology and Virology Laboratory, La Jolla, California 92037, USA.
出版信息
Mol Biol Cell. 1999 Dec;10(12):4043-57. doi: 10.1091/mbc.10.12.4043.
The minichromosome maintenance (MCM) proteins MCM2-MCM7 are conserved eukaryotic replication factors that assemble in a heterohexameric complex. In fission yeast, these proteins are nuclear throughout the cell cycle. In studying the mechanism that regulates assembly of the MCM complex, we analyzed the cis and trans elements required for nuclear localization of a single subunit, Mcm2p. Mutation of any single mcm gene leads to redistribution of wild-type MCM subunits to the cytoplasm, and this redistribution depends on an active nuclear export system. We identified the nuclear localization signal sequences of Mcm2p and showed that these are required for nuclear targeting of other MCM subunits. In turn, Mcm2p must associate with other MCM proteins for its proper localization; nuclear localization of MCM proteins thus requires assembly of MCM proteins in a complex. We suggest that coupling complex assembly to nuclear targeting and retention ensures that only intact heterohexameric MCM complexes remain nuclear.
微小染色体维持（MCM）蛋白MCM2 - MCM7是保守的真核生物复制因子，它们组装成异源六聚体复合物。在裂殖酵母中，这些蛋白在整个细胞周期中都位于细胞核内。在研究调节MCM复合物组装的机制时，我们分析了单个亚基Mcm2p核定位所需的顺式和反式元件。任何单个mcm基因突变都会导致野生型MCM亚基重新分布到细胞质中，而这种重新分布依赖于活跃的核输出系统。我们鉴定了Mcm2p的核定位信号序列，并表明这些序列是其他MCM亚基核靶向所必需的。反过来，Mcm2p必须与其他MCM蛋白结合才能正确定位；因此，MCM蛋白的核定位需要MCM蛋白在复合物中组装。我们认为，将复合物组装与核靶向和保留相耦合可确保只有完整的异源六聚体MCM复合物保留在细胞核内。
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