His1 and His2 are distantly related, spindle-shaped haloviruses belonging to the novel virus group, Salterprovirus
His1 and His2 are distantly related, spindle-shaped haloviruses belonging to the novel virus group, Salterprovirus
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DOI：
10.1016/j.virol.2006.02.005
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发表时间：
2006-06-20
期刊：
影响因子：
3.7
通讯作者：
Dyall-Smith, Michael L.
中科院分区：
文献类型：
--
作者：
Bath, Carolyn;Cukalac, Tania;Dyall-Smith, Michael L.
梭形病毒是高盐沃茨中的主要形态型，但其分子特征及其与其他古细菌病毒的关系尚未确定。本文描述了His 2的分离、特征和基因组序列，并与已报道的HisL进行了比较。结果表明，His 2与HisL的颗粒大小、宿主范围和浮力密度相似，但对高温、低盐度和氯仿的稳定性不同。两种病毒的基因组均为线性dsDNA，大小相似（His 1，14，464 bp; His 2，16，067 bp），mol% G + C（相似于40%），具有长的反向末端重复序列。两种病毒的基因组末端都可能具有结合蛋白。它们几乎没有核苷酸相似性，除了它们推定的DNA聚合酶ORF，在预测的蛋白质水平上没有显著的相似性。这两种病毒的35个预测的ORF中有几个与GenBank中的序列显示出显著的匹配，并且这些总是与盐古菌的蛋白质相匹配。它们的DNA聚合酶显示42%的氨基酸同一性，属于使用蛋白质引发的复制酶的B型组。纯化的His 2颗粒由四种主要蛋白质（62、36、28和21 kDa）组成，并且鉴定了主要衣壳蛋白的基因。类似于His 2 VP 1的假设蛋白存在于四个盐古菌基因组中，但不是完整前噬菌体的一部分。这一点和其他证据表明，晕轮病毒与其宿主之间的重组频率很高。HisI和His 2与梭状病毒不同，并已被置于一个新的病毒组，Salterprovirus。(c)2006年爱思唯尔公司All rights reserved.
Spindle-shaped viruses are a dominant morphotype in hypersaline waters but their molecular characteristics and their relationship to other archaeal viruses have not been determined. Here, we describe the isolation, characteristics and genome sequence of His2, a spindle-shaped halovirus, and compare it to the previously reported halovirus His L Their particle dimensions, host-ranges and buoyant densities were found to be similar but they differed in their stabilities to raised temperature, low salinity and chloroform. The genomes of both viruses were linear dsDNA, of similar size (His 1, 14,464 bp; His2, 16,067 bp) and mol% G + C (similar to 40%), with long, inverted terminal repeat sequences. The genomic termini of both viruses are likely to possess bound proteins. They shared little nucleotide similarity and, except for their putative DNA polymerase ORFs, no significant similarity at the predicted protein level. A few of the 35 predicted ORFs of both viruses showed significant matches to sequences in GenBank, and these were always to proteins of haloarchaea. Their DNA polymerases showed 42% aa identity, and belonged to the type B group of replicases that use protein-priming. Purified His2 particles were composed of four main proteins (62, 36, 28 and 21 kDa) and the gene for the major capsid protein was identified. Hypothetical proteins similar to His2 VP1 are present in four haloarchaeal genomes but are not part of complete prophages. This, and other evidence, suggests a high frequency of recombination between haloviruses and their hosts. His I and His2 are unlike fuselloviruses and have been placed in a new virus group, Salterprovirus. (c) 2006 Elsevier Inc. All rights reserved.