Parvoviruses are small, rugged, nonenveloped protein particles containing a linear, nonpermuted, single-stranded DNA genome of ∼5 kb. Their limited coding potential requires optimal adaptation to the environment of particular host cells, where entry is mediated by a variable program of capsid dynamics, ultimately leading to genome ejection from intact particles within the host nucleus. Genomes are amplified by a continuous unidirectional strand-displacement mechanism, a linear adaptation of rolling circle replication that relies on the repeated folding and unfolding of small hairpin telomeres to reorient the advancing fork. Progeny genomes are propelled by the viral helicase into the preformed capsid via a pore at one of its icosahedral fivefold axes. Here we explore how the fine-tuning of this unique replication system and the mechanics that regulate opening and closing of the capsid fivefold portals have evolved in different viral lineages to create a remarkably complex spectrum of phenotypes.

中文翻译：

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细小病毒：小并不意味着简单。

细小病毒是小的，坚固，无包膜的蛋白质颗粒，包含约5 kb的线性，未排列的单链DNA基因组。它们有限的编码潜能要求对特定宿主细胞的环境进行最佳适应，其中进入过程由衣壳动力学的可变程序介导，最终导致宿主核内完整颗粒的基因组弹出。基因组通过连续的单向链置换机制进行扩增，这是滚环复制的线性适应方式，它依赖于小发夹端粒的反复折叠和解折叠来重新定位前进的叉子。子代基因组被病毒解旋酶通过其二十面体五倍轴之一的孔推进到预先形成的衣壳中。