Esteban R, Wickner R B
Section on Genetics of Simple Eukaryotes, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892.
J Virol. 1988 Apr;62(4):1278-85. doi: 10.1128/JVI.62.4.1278-1285.1988.
X double-stranded RNA (dsRNA) is a 0.52-kilobase dsRNA molecule that arose spontaneously in a nonkiller strain of Saccharomyces cerevisiae originally containing L-A and L-BC dsRNAs (L-BC is the same size as L-A but shares no homology with it). X hybridized with L-A, and direct RNA sequencing of X showed that the first 5' 25 base pairs (of the X positive strand) and at least the last 110 base pairs of the 3' end were identical to the ends of L-A dsRNA. X showed cytoplasmic inheritance and, like M1, was dependent on L-A for its maintenance. X was encapsidated in viruslike particles whose major coat protein was provided by L-A (as is true for M1), and X was found in viruslike particles with one to eight X molecules per particle. This finding confirms our "head-full replication" model originally proposed for M1 and M2. Like M1 or M2, X lowers the copy number of L-A, especially in a ski host. Surprisingly, X requires many chromosomal MAK genes that are necessary for M1 but not for L-A.
X双链RNA（dsRNA）是一种0.52千碱基的双链RNA分子，它在最初含有L-A和L-BC双链RNA的酿酒酵母非杀伤菌株中自发产生（L-BC与L-A大小相同，但与之无同源性）。X与L-A杂交，对X进行直接RNA测序表明，（X正链的）前5'端25个碱基对以及3'端至少最后110个碱基对与L-A双链RNA的末端相同。X表现出细胞质遗传，并且像M1一样，其维持依赖于L-A。X被包裹在病毒样颗粒中，其主要衣壳蛋白由L-A提供（M1也是如此），并且在每个颗粒含有一到八个X分子的病毒样颗粒中发现了X。这一发现证实了我们最初为M1和M2提出的“满头部复制”模型。与M1或M2一样，X会降低L-A的拷贝数，尤其是在ski宿主中。令人惊讶的是，X需要许多M1所需但L-A不需要的染色体MAK基因。
