Point mutations in the ICR2 motif of brome mosaic virus RNAs debilitate (+)-strand replication.
Point mutations in the ICR2 motif of brome mosaic virus RNAs debilitate (+)-strand replication.
复制标题
雀麦花叶病毒 RNA 的 ICR2 基序中的点突变会削弱 ( ) 链复制。
DOI：
10.1016/0042-6822(90)90388-8
复制
发表时间：
1990
期刊：
影响因子：
3.7
通讯作者：
Hall,TC
中科院分区：
文献类型：
--
作者：
Pogue,GP;Marsh,LE;Hall,TC
雀麦花叶病毒（BMV）和其它（+）链RNA病毒的基因组RNA的5′末端序列已经显示（L. E. Marsh和T. C.霍尔，1987年，冷泉港研讨会。定量Biol.52，331-341）类似于tRNA基因的ICR 1和2（A和B盒），（-）链3′末端的互补序列类似于甲硫氨酸起始物tRNA基因的ICR 2基序（L. E. Marsh，G. P. Pogue和T. C. Hall，1989，Virology 172，415-427）。为了研究这些序列在病毒复制中的作用，将点突变引入BMV RNA-2缺失突变体pRNA ΔM/S（寄生RNA）的ICR 2样序列中，该突变体不编码功能性病毒蛋白，但在基因组RNA-1和-2存在下复制。在（+）-有义ICR 2-like基序的A7或T8位引入单碱基取代使pRNA ΔM/S复制减少70- 82%，动力学分析显示主要影响是（+）-链合成的减弱。这些基序是否以类似于tRNA基因的方式或通过3′（-）链上的tRNAMeti样序列以（+）-有义方向起作用仍有待确定，但数据清楚地表明BMV RNA的ICR样区域内的碱基组成对（+）-链启动子功能有很大贡献。
Sequences at the 5′ termini of the genomic RNAs of brome mosaic virus (BMV) and other (+)-stranded RNA viruses have been shown (L. E. Marsh and T. C. Hall, 1987,Cold Spring Harbor Symp. Quant. Biol.52, 331–341) to resemble the ICRs 1 and 2 (A and B boxes) of tRNA genes, with the complementary sequences at the 3′ termini of the (−) strands resembling the ICR2 motif of methionine initiator tRNA genes (L. E. Marsh, G. P. Pogue, and T. C. Hall, 1989,Virology172, 415–427). In order to examine the role of these sequences in viral replication, point mutations have been introduced into the ICR2-like sequence of a BMV RNA-2 deletion mutant, pRNA ΔM/S (parasitic RNA), that does not encode a functional viral protein but replicates in the presence of genomic RNA-1 and -2. Single-base substitutions introduced at positions A7or T8of the (+)-sense ICR2-like motif reduced pRNA ΔM/S replication by 70–82%, the primary effect being shown by kinetic analyses to be debilitation of (+)-strand synthesis. Whether these motifs act in their (+)-sense orientation in a manner analogous to tRNA genes or through the tRNAMeti-like sequence on the 3′ (−) strand remains to be determined, but the data clearly demonstrate that the base composition within the ICR-like region of BMV RNAs contributes greatly to (+)-strand promoter function.