González-Huici Víctor, Salas Margarita, Hermoso José M
Instituto de Biología Molecular Eladio Viñuela (CSIC), Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain.
Mol Microbiol. 2004 Apr;52(2):529-40. doi: 10.1111/j.1365-2958.2004.03993.x.
The mechanism of bacteriophage DNA injection is poorly understood, often considered a simple process, driven merely by the packing pressure inside the capsid. In contrast to the well-established DNA packaging mechanism of Bacillus subtilis phage Ø29, that involves a molecular motor formed by the connector and a viral ATPase, nothing is known about its DNA injection into the cell. We have studied this process measuring DNA binding of p6, a viral genome organization protein. The linear DNA penetrates with a right-left polarity, in a two-step process. In the first step approximately 65% of the genome is pushed into the cell most probably by the pressure built inside the viral capsid. Thus, synthesis of viral proteins from the right early operon is allowed. This step is controlled, probably by bacterial protein(s) that slow down DNA entry. In the second step at least one of the viral early proteins, p17, participates in the molecular machinery that pulls the remaining DNA inside the cell. Both steps are energy-dependent, as treatment of cells with azide overrides the whole mechanism, leading to a deregulated, passive entry of DNA.
噬菌体DNA注入的机制尚不清楚，通常被认为是一个简单的过程，仅仅由衣壳内部的包装压力驱动。与枯草芽孢杆菌噬菌体Ø29已确立的DNA包装机制（涉及由连接体和病毒ATP酶形成的分子马达）不同，关于其DNA注入细胞的情况一无所知。我们通过测量病毒基因组组织蛋白p6的DNA结合来研究这一过程。线性DNA以左右极性，分两步进入。第一步，大约65%的基因组很可能被病毒衣壳内部产生的压力推入细胞。因此，允许从右侧早期操纵子合成病毒蛋白。这一步骤可能受细菌蛋白控制，这些细菌蛋白会减缓DNA进入。在第二步中，至少一种病毒早期蛋白p17参与将剩余DNA拉入细胞的分子机制。这两个步骤都依赖能量，因为用叠氮化物处理细胞会破坏整个机制，导致DNA无节制地被动进入。
