Initial cos cleavage of bacteriophage lambda concatemers requires proheads and gpFI in vivo.
Initial cos cleavage of bacteriophage lambda concatemers requires proheads and gpFI in vivo.
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噬菌体 lambda 串联体的初始 cos 切割需要体内的 proheads 和 gpFI。
DOI：
10.1111/j.1365-2958.2004.03990.x
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Feiss,Michael
中科院分区：
文献类型：
--
作者：
Sippy,Jean;Feiss,Michael
噬菌体λ和双链DNA病毒的发展通常涉及两个独立途径的融合：DNA复制和头部组装。显然，只有当空的衣壳壳（即前头部）存在以接收DNA时，包装才会进行，但遗传证据表明，前头部在包装过程中扮演着另一个角色。例如，在任何头部基因或inFI（编码辅助包装蛋白gpFI的基因）中具有琥珀突变的λ π ι能够产生正常量的DNA多联体，但它们不被切割或成熟为单位长度的染色体用于包装。对单纯疱疹病毒1也有类似的观察。在λ的情况下，一个负模型提出，在琥珀酰亚胺中，未组装的衣壳组分对成熟具有抑制作用，而一个正模型表明，组装的前头部是切割所必需的。我们在体内共切割试验中使用缺乏所有前头基因和FI的缺失突变体来测试阴性模型;在这种缺失的噬菌体中，粘性末端没有被切割。当λ proheads和gpFI通过第二个原噬菌体在体内提供时，切割恢复，并且需要gpFI，结果支持阳性模型。噬菌体21是λ的姐妹噬菌体，尽管其衣壳蛋白与λ共享约60%的残基同一性，但噬菌体21的前头部不能恢复切割，即使提供有辅助蛋白gpFI。模型的作用proheads和gpFI incoscutting进行了讨论。
The development of bacteriophage λ and double‐stranded DNA viruses in general involves the convergence of two separate pathways: DNA replication and head assembly. Clearly, packaging will proceed only if an empty capsid shell, the prohead, is present to receive the DNA, but genetic evidence suggests that proheads play another role in the packaging process. For example, λ phages with an amber mutation in any head gene or inFI, the gene encoding the accessory packaging protein gpFI, are able to produce normal amounts of DNA concatemers but they are not cut, or matured, into unit length chromosomes for packaging. Similar observations have been made for herpes simplex 1 virus. In the case of λ, a negative model proposes that in the amber phages, unassembled capsid components are inhibitory to maturation, and a positive model suggests that assembled proheads are required for cutting. We tested the negative model by using a deletion mutant devoid of all prohead genes andFIin anin vivo coscleavage assay; in this deleted phage, the cohesive ends were not cut. When λ proheads and gpFI were providedin vivovia a second prophage, cutting was restored, and gpFI was required, results that support the positive model. Phage 21 is a sister phage of λ, and although its capsid proteins share ∼60% residue identity with λ’s, phage 21 proheads did not restore cutting, even when provided with the accessory protein gpFI. Models for the role of proheads and gpFI incoscutting are discussed.