A novel motif in geminivirus replication proteins interacts with the plant retinoblastoma-related protein
A novel motif in geminivirus replication proteins interacts with the plant retinoblastoma-related protein
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DOI：
10.1128/jvi.78.9.4817-4826.2004
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发表时间：
2004-05-01
影响因子：
5.4
通讯作者：
Hanley-Bowdoin, L
中科院分区：
文献类型：
--
作者：
Arguello-Astorga, G;Lopez-Ochoa, L;Hanley-Bowdoin, L
双生病毒复制因子AL 1与植物视网膜母细胞瘤相关蛋白（pRBR）相互作用以调节宿主基因表达。番茄金色花叶病毒（TGMV）的AL 1蛋白通过含有两个高度预测的α-螺旋（指定为3和4）的80个氨基酸的区域结合到pRBR。早期的研究表明，螺旋4基序，其氨基酸序列在双生病毒复制蛋白中高度保守，在pRBR结合中起作用。我们在TGMV AL 1的螺旋4上产生了一系列丙氨酸取代，并使用酵母双杂交试验研究了它们对pRBR结合的影响。这些实验表明，几个螺旋4残基对于有效的pRBR结合是必不可少的，其中关键残基是基序中间位置148处的亮氨酸。亮氨酸-148处的各种氨基酸取代表明结构和侧链组分都有助于pRBR结合。在酵母双杂交试验中，双生病毒属番茄黄化曲叶病毒和卷心菜曲叶病毒的复制蛋白也与pRBR结合。CaLCuV AL 1螺旋4中亮氨酸残基的突变降低了结合。总之，这些结果表明，螺旋4和保守的亮氨酸残基是菜豆花叶病毒复制蛋白中pRBR结合界面的一部分。
The geminivirus replication factor AL1 interacts with the plant retinoblastoma-related protein (pRBR) to modulate host gene expression. The AL1 protein of tomato golden mosaic virus (TGMV) binds to pRBR through an 80-amino-acid region that contains two highly predicted alpha-helices designated 3 and 4. Earlier studies suggested that the helix 4 motif, whose amino acid sequence is strongly conserved across geminivirus replication proteins, plays a role in pRBR binding. We generated a series of alanine substitutions across helix 4 of TGMV AL1 and examined their impact on pRBR binding using yeast two-hybrid assays. These experiments showed that several helix 4 residues are essential for efficient pRBR binding, with a critical residue being a leucine at position 148 in the middle of the motif. Various amino acid substitutions at leucine-148 indicated that both structural and side chain components contribute to pRBR binding. The replication proteins of the geminiviruses tomato yellow leaf curl virus and cabbage leaf curl virus (CaLCuV) also bound to pRBR in yeast dihybrid assays. Mutation of the leucine residue in helix 4 of CaLCuV AL1 reduced binding. Together, these results suggest that helix 4 and the conserved leucine residue are part of a pRBR-binding interface in begomovirus replication proteins.