The N-terminal domain of y-box binding protein-1 induces cell cycle arrest in g2/m phase by binding to cyclin d1.
The N-terminal domain of y-box binding protein-1 induces cell cycle arrest in g2/m phase by binding to cyclin d1.
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DOI：
10.1155/2009/243532
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发表时间：
2009
影响因子：
--
通讯作者：
Guntaka RV
中科院分区：
文献类型：
--
作者：
Khandelwal P;Padala MK;Cox J;Guntaka RV
Y-box结合蛋白YB-1是一种参与细胞增殖、转录和翻译调节的多功能蛋白。我们之前的研究表明，DT-40 细胞中 Chk-YB-1b 基因的一个等位基因的破坏导致细胞周期的重大缺陷。杂合突变体中观察到的异常可能归因于受破坏的 YB-1 等位基因产物所产生的显性负效应。为了验证这一假设，将 YB-1 的 N 端序列与触角的第三螺旋和绿色荧光蛋白融合。将这些纯化的融合蛋白引入大鼠肝癌细胞并研究它们对细胞增殖的影响。结果表明，YB-1蛋白的N端77个氨基酸结构域诱导细胞停滞在细胞周期的G2/M期并发生凋亡。额外的缺失分析表明，YB-1 N 末端的 26 个氨基酸即可引起这些表型变化。我们进一步证明，YB-1 的 N 端 77 个氨基酸结构域将细胞周期蛋白 D1 隔离在细胞周期 G2/M 期细胞的细胞质中。我们得出结论，YB-1 的 N 端结构域在细胞周期 G2/M 期的细胞周期进程中发挥着重要作用。
Y-box binding protein YB-1 is a multifunctional protein involved in cell proliferation, regulation of transcription and translation. Our previous study indicated that disruption of one allele of Chk-YB-1b gene in DT-40 cells resulted in major defects in the cell cycle. The abnormalities seen in heterozygous mutants could be attributed to a dominant negative effect exerted by the disrupted YB-1 allele product. To test this hypothesis the N-terminal sequence of the YB-1 was fused with the third helix of antennapedia and the green fluorescent protein. These purified fusion proteins were introduced into rat hepatoma cells and their effect on cell proliferation was studied. Results indicate that the N-terminal 77 amino acid domain of the YB-1 protein induced the cells to arrest in G2/M phase of the cell cycle and undergo apoptosis. Additional deletion analysis indicated that as few as 26 amino acids of the N-terminus of YB-1 can cause these phenotypic changes. We further demonstrated that this N-terminal 77 amino acid domain of YB-1 sequesters cyclin D1 in the cytoplasm of cells at G2/M phase of cell cycle. We conclude that the N-terminal domain of YB-1 plays a major role in cell cycle progression through G2/M phase of cell cycle.