Prangishvili David, Vestergaard Gisle, Häring Monika, Aramayo Ricardo, Basta Tamara, Rachel Reinhard, Garrett Roger A
Molecular Biology of the Gene in Extremophiles Unit, Institut Pasteur, Paris, France.
J Mol Biol. 2006 Jun 23;359(5):1203-16. doi: 10.1016/j.jmb.2006.04.027. Epub 2006 Apr 27.
A novel virus, ATV, of the hyperthermophilic archaeal genus Acidianus has the unique property of undergoing a major morphological development outside of, and independently of, the host cell. Virions are extruded from host cells as lemon-shaped tail-less particles, after which they develop long tails at each pointed end, at temperatures close to that of the natural habitat, 85 degrees C. The extracellularly developed tails constitute tubes, which terminate in an anchor-like structure that is not observed in the tail-less particles. A thin filament is located within the tube, which exhibits a periodic structure. Tail development produces a one half reduction in the volume of the virion, concurrent with a slight expansion of the virion surface. The circular, double-stranded DNA genome contains 62,730 bp and is exceptional for a crenarchaeal virus in that it carries four putative transposable elements as well as genes, which previously have been associated only with archaeal self-transmissable plasmids. In total, it encodes 72 predicted proteins, including 11 structural proteins with molecular masses in the range of 12 to 90 kDa. Several of the larger proteins are rich in coiled coil and/or low complexity sequence domains, which are unusual for archaea. One protein, in particular P800, resembles an intermediate filament protein in its structural properties. It is modified in the two-tailed, but not in the tail-less, virion particles and it may contribute to viral tail development. Exceptionally for a crenarchaeal virus, infection with ATV results either in viral replication and subsequent cell lysis or in conversion of the infected cell to a lysogen. The lysogenic cycle involves integration of the viral genome into the host chromosome, probably facilitated by the virus-encoded integrase and this process can be interrupted by different stress factors.
一种新型病毒——嗜热古菌嗜酸热原体属的ATV，具有在宿主细胞外且独立于宿主细胞进行主要形态发育的独特特性。病毒粒子以柠檬形无尾颗粒的形式从宿主细胞中挤出，之后在接近其自然栖息地温度85摄氏度的条件下，在每个尖端长出长尾巴。细胞外发育的尾巴构成管子，其末端是无尾颗粒中未观察到的锚状结构。一根细丝位于管内，呈现出周期性结构。尾巴发育使病毒粒子体积减少一半，同时病毒粒子表面略有扩张。环状双链DNA基因组包含62,730个碱基对，对于泉古菌病毒来说是例外，因为它携带四个假定的转座元件以及以前仅与古菌自我传递质粒相关的基因。它总共编码72个预测蛋白，包括11个分子量在12至90 kDa范围内的结构蛋白。几个较大的蛋白富含卷曲螺旋和/或低复杂性序列结构域，这在古菌中是不常见的。特别是一种蛋白P800，其结构特性类似于中间丝蛋白。它在有尾病毒粒子中被修饰，但在无尾病毒粒子中未被修饰，可能有助于病毒尾巴的发育。与泉古菌病毒不同的是，感染ATV要么导致病毒复制和随后的细胞裂解，要么导致受感染细胞转变为溶原菌。溶原周期涉及病毒基因组整合到宿主染色体中，可能由病毒编码的整合酶促进，并且这个过程可以被不同的应激因素中断。
