Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid, Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain.
Proc Natl Acad Sci U S A. 2012 Nov 6;109(45):18482-7. doi: 10.1073/pnas.1216635109. Epub 2012 Oct 22.
A number of prokaryotic proteins have been shown to contain nuclear localization signals (NLSs), although its biological role remains sometimes unclear. Terminal proteins (TPs) of bacteriophages prime DNA replication and become covalently linked to the genome ends. We predicted NLSs within the TPs of bacteriophages from diverse families and hosts and, indeed, the TPs of Φ29, Nf, PRD1, Bam35, and Cp-1, out of seven TPs tested, were found to localize to the nucleus when expressed in mammalian cells. Detailed analysis of Φ29 TP led us to identify a bona fide NLS within residues 1-37. Importantly, gene delivery into the eukaryotic nucleus is enhanced by the presence of Φ29 TP attached to the 5' DNA ends. These findings show a common feature of TPs from diverse bacteriophages targeting the eukaryotic nucleus and suggest a possible common function by facilitating the horizontal transfer of genes between prokaryotes and eukaryotes.
已经有许多原核蛋白被证明含有核定位信号（NLS），尽管其生物学作用有时仍不清楚。噬菌体的末端蛋白（TP）启动 DNA 复制，并与基因组末端共价连接。我们预测了来自不同科和宿主的噬菌体 TP 中的 NLS，实际上，在所测试的七个 TP 中，当在哺乳动物细胞中表达时，Φ29、Nf、PRD1、Bam35 和 Cp-1 的 TP 被发现定位于细胞核。对 Φ29 TP 的详细分析使我们能够在残基 1-37 内识别出一个真正的 NLS。重要的是，附着在 5' DNA 末端的 Φ29 TP 增强了基因向真核细胞核的传递。这些发现表明了来自不同噬菌体的 TP 靶向真核细胞核的共同特征，并通过促进原核生物和真核生物之间基因的水平转移，暗示了一种可能的共同功能。
