Accumulation of alfalfa mosaic virus RNAs 1 and 2 requires the encoded proteins in cis
Accumulation of alfalfa mosaic virus RNAs 1 and 2 requires the encoded proteins in cis
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DOI：
10.1128/jvi.70.8.5100-5105.1996
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发表时间：
1996-08
影响因子：
5.4
通讯作者：
C. V. van Rossum;M. L. García;J. Bol
中科院分区：
文献类型：
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作者：
C. V. van Rossum;M. L. García;J. Bol
苜蓿花叶病毒(A1MV)三部分基因组的RNA1和RNA2分别编码复制酶蛋白P1和P2。在转基因植株(P1植株)中表达的P1可以用来反式支持A1 MV RNA2和3的复制，而在转基因植物(P2植株)中表达的P2可以用于反式支持A1 MV RNA1和A1MV RNA3的复制。野生型RNA1能够在P1植株中与RNA2和RNA3共复制，但这种能力被RNA1的P1基因的移码或缺失所取消。同样，野生型RNA2与P2中的RNA1和RNA3共复制，但RNA2的P2基因的移码或缺失干扰了这种复制。显然，在顺式病毒中，P1和P2基因分别是RNAs1和RNAs2积累所必需的。RNA2中P2基因GDD基序的点突变干扰了RNA2在P2植物中的积累，表明RNA2的复制与其翻译成功能蛋白有关。同时转化P1和P2基因的植株(P12植株)积累了能够以反式方式复制RNA3的复制酶活性。对P12植株原生质体中RNA1、2和3积累的时间进程的分析支持这样的结论：A1 MV RNA1和2的翻译和复制紧密耦合，而RNA3不是。
RNAs 1 and 2 of the tripartite genome of alfalfa mosaic virus (A1MV) encode the replicase proteins P1 and P2, respectively. P1 expressed in transgenic plants (P1 plants) can be used in trans to support replication of A1MV RNAs 2 and 3, and P2 expressed in transgenic plants (P2 plants) can be used in trans to support replication of A1MV RNAs 1 and 3. Wild-type RNA 1 was able to coreplicate with RNAs 2 and 3 in P1 plants, but this ability was abolished by frameshifts or deletions in the P1 gene of RNA 1. Similarly, wild-type RNA 2 coreplicated with RNAs 1 and 3 in P2 plants, but frameshifts or deletions in the P2 gene of RNA 2 interfered with this replication. Apparently, the P1 and P2 genes are required in cis for the accumulation of RNAs 1 and 2, respectively. Point mutations in the GDD motif of the P2 gene in RNA 2 interfered with accumulation of RNA 2 in P2 plants, indicating that replication of RNA 2 is linked to its translation into a functional protein. Plants transformed with both the P1 and P2 genes (P12 plants) accumulate replicase activity that is able to replicate RNA 3 in trans. An analysis of the time course of the accumulation of RNAs 1, 2, and 3 in protoplasts of P12 plants supported the conclusion that translation and replication are tightly coupled for A1MV RNAs 1 and 2 but not for RNA 3.