噬菌体P22在注入其基因组之前会先排出所有内部蛋白质。
Bacteriophage P22 ejects all of its internal proteins before its genome.
作者信息
Jin Yan, Sdao Sophia M, Dover John A, Porcek Natalia B, Knobler Charles M, Gelbart William M, Parent Kristin N
机构信息
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
Michigan State University, Department of Biochemistry and Molecular Biology, East Lansing, MI 48824, USA.
出版信息
Virology. 2015 Nov;485:128-34. doi: 10.1016/j.virol.2015.07.006. Epub 2015 Aug 1.
Double-stranded DNA bacteriophages are highly pressurized, providing a force driving ejection of a significant fraction of the genome from its capsid. In P22-like Podoviridae, internal proteins ("E proteins") are packaged into the capsid along with the genome, and without them the virus is not infectious. However, little is known about how and when these proteins come out of the virus. We employed an in vitro osmotic suppression system with high-molecular-weight polyethylene glycol to study P22 E protein release. While slow ejection of the DNA can be triggered by lipopolysaccharide (LPS), the rate is significantly enhanced by the membrane protein OmpA from Salmonella. In contrast, E proteins are not ejected unless both OmpA and LPS are present and their ejection when OmpA is present is largely complete before any genome is ejected, suggesting that E proteins play a key role in the early stage of transferring P22 DNA into the host.
双链DNA噬菌体处于高压状态，能产生一种力，促使很大一部分基因组从衣壳中释放出来。在P22样短尾病毒科中，内部蛋白（“E蛋白”）与基因组一起被包装进衣壳，没有这些蛋白，病毒就没有传染性。然而，对于这些蛋白如何以及何时从病毒中释放出来，人们知之甚少。我们采用了一种含有高分子量聚乙二醇的体外渗透抑制系统来研究P22 E蛋白的释放。虽然脂多糖（LPS）可触发DNA的缓慢释放，但沙门氏菌的膜蛋白OmpA能显著提高释放速率。相比之下，除非同时存在OmpA和LPS，否则E蛋白不会释放，而且当存在OmpA时，E蛋白的释放基本上在任何基因组释放之前就已完成，这表明E蛋白在将P22 DNA转移到宿主的早期阶段起着关键作用。
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