Yeast virus-like particles possess a capsid-associated single-stranded RNA polymerase
Yeast virus-like particles possess a capsid-associated single-stranded RNA polymerase
复制标题
酵母病毒样颗粒具有衣壳相关的单链RNA聚合酶
作者：
A. Herring;E. Bevan
许多种类的真菌都具有带有双链RNA（dsRNA）基因组的病毒样颗粒1，2。在酵母中，dsRNA基因组已被证明是“杀手”特征的遗传决定因素3 -10。没有裂解和再感染的循环已被证明为这个组的“病毒”和复制是集成与主机growth 1，2。来自几种真菌的颗粒已经显示出具有RNA聚合酶活性，并且我们已经表明从生长细胞中分离的酵母颗粒合成dsRNA（参考文献11-14）。我们在这里报告，从非生长细胞中分离的颗粒合成dsRNA和单链（ssRNA）物质，其性质表明它是dsRNA基因组的完整转录物。我们对来自生长细胞的颗粒的研究结果表明，酵母“病毒”的复制周期类似于呼肠孤病毒14，并且不通过巴克13提出的“倍增周期”发生，以解释他对匍匐青霉S的研究结果。病毒酵母颗粒中ssRNA聚合酶活性的发现与呼肠孤病毒类型的复制周期一致。
MANY species of fungi possess virus-like particles with double-stranded RNA (dsRNA) genomes1,2. In yeast the dsRNA genome has been shown to be the genetic determinant of the ‘killer’ character3–10. No cycle of lysis and reinfection has been demonstrated for ‘viruses’ of this group and replication is integrated with host growth1,2. Particles from several species of fungi have been shown to possess RNA polymerase activity and we have shown that yeast particles isolated from growing cells synthesise dsRNA (refs 11–14). We report here that particles isolated from non-growing cells synthesise both dsRNA and a single-stranded (ssRNA) species with properties suggesting that it is a complete transcript of the dsRNA genome. Our results with particles from growing cells suggested that the replicative cycle of yeast ‘virus’ resembles that of reovirus14 and does not occur through the ‘doubling cycle’ which was put forward by Buck13 to account for his results with Penicillium stoloniferum S. virus. The discovery of a ssRNA polymerase activity in yeast particles is consistent with the reovirus type of replicative cycle.