Dominguez G, Wang C Y, Frey T K
Department of Biology, Georgia State University, Atlanta 30302-4010.
Virology. 1990 Jul;177(1):225-38. doi: 10.1016/0042-6822(90)90476-8.
The nucleotide sequence of the rubella virus (RUB) genomic RNA was determined. The RUB genomic RNA is 9757 nucleotides in length [excluding the poly(A) tail] and has a G/C content of 69.5%, the highest of any RNA virus sequenced to data. The RUB genomic RNA contains two long open reading frames (ORFs), a 5'-proximal ORF of 6656 nucleotides and a 3'-proximal ORF of 3189 nucleotides which encodes the structural proteins. Thus, the genomic organization of RUB is similar to that of alphaviruses, the other genus of the Togavirus family, and the 5'-proximal ORF of RUB therefore putatively codes for the nonstructural proteins. Sequences homologous to three regions of nucleotide sequence highly conserved among alphaviruses (a stem-and-loop structure at the 5' end of the genome, a 51-nucleotide conserved sequence near the 5' end of the genome, and a 20-nucleotide conserved sequence at the subgenomic RNA start site) were found in the RUB genomic RNA. Amino acid sequence comparisons between the nonstructural ORF of RUB and alphaviruses revealed only one short (122 amino acids) region of significant homology, indicating that these viruses are only distantly related. This region of homology is located at the NH2 terminus of nsP3 in the alphavirus genome. The RUB nonstructural protein ORF contains two global amino acid motifs conserved in a large number of positive-polarity RNA viruses, a motif indicative of helicase activity and a motif indicative of replicase activity. The order of the helicase motif and the nsP3 homology region in the RUB genome is reversed with respect to the alphavirus genome indicating that a genetic rearrangement has occurred during the evolution of these viruses.
测定了风疹病毒（RUB）基因组RNA的核苷酸序列。RUB基因组RNA长度为9757个核苷酸[不包括聚（A）尾]，G/C含量为69.5%，是迄今测序的所有RNA病毒中最高的。RUB基因组RNA包含两个长开放阅读框（ORF），一个5'近端的6656个核苷酸的ORF和一个3'近端的3189个核苷酸的ORF，后者编码结构蛋白。因此，RUB的基因组结构与披膜病毒科的另一属——甲病毒属相似，所以RUB的5'近端ORF推测编码非结构蛋白。在RUB基因组RNA中发现了与甲病毒中三个核苷酸序列高度保守区域同源的序列（基因组5'端的茎环结构、基因组5'端附近的一个51个核苷酸的保守序列以及亚基因组RNA起始位点的一个20个核苷酸的保守序列）。RUB非结构ORF与甲病毒之间的氨基酸序列比较仅显示出一个短的（122个氨基酸）显著同源区域，表明这些病毒亲缘关系较远。这个同源区域位于甲病毒基因组中nsP3的NH2末端。RUB非结构蛋白ORF包含两个在大量正链RNA病毒中保守的全局氨基酸基序，一个指示解旋酶活性的基序和一个指示复制酶活性的基序。RUB基因组中解旋酶基序和nsP3同源区域的顺序相对于甲病毒基因组是相反的，这表明在这些病毒的进化过程中发生了基因重排。
