Independent functions of viral protein and nucleic acid in growth of bacteriophage.
Independent functions of viral protein and nucleic acid in growth of bacteriophage.
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DOI：
10.1085/jgp.36.1.39
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发表时间：
1952-05
期刊：
影响因子：
--
通讯作者：
CHASE M
中科院分区：
文献类型：
--
作者：
HERSHEY AD;CHASE M
1. 渗透性休克将T2噬菌体的颗粒破坏成含有几乎所有噬菌体硫的物质，这种物质以抗噬菌体血清可沉淀的形式存在，并且能够对细菌进行特异性吸附。它将几乎所有的噬菌体DNA以一种抗血清不能沉淀的形式释放到溶液中，也不能被细菌吸附。噬菌体颗粒的含硫蛋白质显然构成了一层膜，保护噬菌体DNA免受DNA酶的侵害，它是唯一或主要的抗原物质，并负责将病毒附着在细菌上。2. 将T2吸附到热杀死的细菌上，加热或交替冷冻和解冻被感染的细胞，使被吸附的噬菌体的DNA对DNA酶敏感。这些处理对未吸附的噬菌体几乎没有或没有增敏作用。加热或冷冻和解冻都不能从感染细胞中释放噬菌体DNA，尽管这些方法可以提取其他细胞成分。这些事实表明，噬菌体DNA在整个噬菌体生长期间形成了有组织的细胞内结构的一部分。3. 噬菌体T2对细菌碎片的吸附导致部分噬菌体DNA出现在溶液中，使噬菌体硫附着在碎片上。噬菌体DNA的另一部分，大致相当于灭活噬菌体的剩余一半DNA，仍然附着在碎片上，但可以通过DNA酶与碎片分离。噬菌体T4的行为类似，尽管这两个噬菌体可以附着在不同的结合位点上。细菌碎片使噬菌体失活的过程明显伴随着病毒膜的破裂。4. 受感染细胞的悬浮液在沃林混合液中搅拌，由于施加的剪切力，将75%的噬菌体硫和15%的噬菌体磷释放到溶液中。这些细胞仍然能够产生噬菌体后代。5. 事实表明，大部分噬菌体硫留在细胞表面，大部分噬菌体DNA在感染时进入细胞。目前还不确定DNA以外的无硫物质是否会进入细胞。含硫残留物的性质确定它是噬菌体颗粒的基本不变的膜。所有类型的证据表明，噬菌体DNA在非营养培养基中进入细胞，而病毒生长的其他已知步骤则不会发生。6. 被标记有放射性硫的噬菌体感染的细菌产生的噬菌体后代所含的放射性低于亲代的1%。标记有放射性磷的噬菌体粒子的后代含有30%或更多的亲本磷。7. 被稀释甲醛灭活的噬菌体能够吸附细菌，但不会将其DNA释放到细胞中。这表明噬菌体与细菌之间的相互作用导致噬菌体DNA从其保护膜上释放取决于噬菌体颗粒的不稳定成分。相比之下，这种相互作用所必需的细菌成分是非常稳定的。除此之外，这种相互作用的性质是未知的。8. 静止的噬菌体颗粒的含硫蛋白质被限制在一层保护外壳内，负责对细菌的吸附，并作为将噬菌体DNA注射到细胞中的工具。这种蛋白可能对细胞内噬菌体的生长没有作用。DNA有一些功能。不应从所提出的实验中得出进一步的化学推论。
1. Osmotic shock disrupts particles of phage T2 into material containing nearly all the phage sulfur in a form precipitable by antiphage serum, and capable of specific adsorption to bacteria. It releases into solution nearly all the phage DNA in a form not precipitable by antiserum and not adsorbable to bacteria. The sulfur-containing protein of the phage particle evidently makes up a membrane that protects the phage DNA from DNase, comprises the sole or principal antigenic material, and is responsible for attachment of the virus to bacteria. 2. Adsorption of T2 to heat-killed bacteria, and heating or alternate freezing and thawing of infected cells, sensitize the DNA of the adsorbed phage to DNase. These treatments have little or no sensitizing effect on unadsorbed phage. Neither heating nor freezing and thawing releases the phage DNA from infected cells, although other cell constituents can be extracted by these methods. These facts suggest that the phage DNA forms part of an organized intracellular structure throughout the period of phage growth. 3. Adsorption of phage T2 to bacterial debris causes part of the phage DNA to appear in solution, leaving the phage sulfur attached to the debris. Another part of the phage DNA, corresponding roughly to the remaining half of the DNA of the inactivated phage, remains attached to the debris but can be separated from it by DNase. Phage T4 behaves similarly, although the two phages can be shown to attach to different combining sites. The inactivation of phage by bacterial debris is evidently accompanied by the rupture of the viral membrane. 4. Suspensions of infected cells agitated in a Waring blendor release 75 per cent of the phage sulfur and only 15 per cent of the phage phosphorus to the solution as a result of the applied shearing force. The cells remain capable of yielding phage progeny. 5. The facts stated show that most of the phage sulfur remains at the cell surface and most of the phage DNA enters the cell on infection. Whether sulfur-free material other than DNA enters the cell has not been determined. The properties of the sulfur-containing residue identify it as essentially unchanged membranes of the phage particles. All types of evidence show that the passage of phage DNA into the cell occurs in non-nutrient medium under conditions in which other known steps in viral growth do not occur. 6. The phage progeny yielded by bacteria infected with phage labeled with radioactive sulfur contain less than 1 per cent of the parental radioactivity. The progeny of phage particles labeled with radioactive phosphorus contain 30 per cent or more of the parental phosphorus. 7. Phage inactivated by dilute formaldehyde is capable of adsorbing to bacteria, but does not release its DNA to the cell. This shows that the interaction between phage and bacterium resulting in release of the phage DNA from its protective membrane depends on labile components of the phage particle. By contrast, the components of the bacterium essential to this interaction are remarkably stable. The nature of the interaction is otherwise unknown. 8. The sulfur-containing protein of resting phage particles is confined to a protective coat that is responsible for the adsorption to bacteria, and functions as an instrument for the injection of the phage DNA into the cell. This protein probably has no function in the growth of intracellular phage. The DNA has some function. Further chemical inferences should not be drawn from the experiments presented.