School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212100, China.
Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Scientific Research Center, Chinese Academy of Agricultural Sciences, Zhenjiang 212100, China.
Int J Mol Sci. 2024 Sep 29;25(19):10521. doi: 10.3390/ijms251910521.
Mulberry crinkle leaf virus (MCLV), identified in mulberry plants ( L.), is a member of the genus in the family . The functions of the V2 protein encoded by MCLV remain unclear. Here, -mediated infectious clones of a wild-type MCLV vII (MCLV) and two V2 mutant MCLV vIIs, including MCLV (with a mutation of the start codon of the V2 ORF) and MCLV (5'-end partial deletion of the V2 ORF sequence), were constructed to investigate the roles of V2 both in planta and at the cellular level. Although all three constructs (pCA-1.1MCLV, pCA-MCLV, and pCA-MCLV) were able to infect both natural host mulberry plants and experimental tomato plants systematically, the replication of the MCLV and MCLV genomes in these hosts was significantly reduced compared to that of MCLV. Similarly, the accumulation of MCLV and MCLV in protoplasts of plants was significantly lower than that of MCLV either 24 h or 48 h post-transfection. A complementation experiment further confirmed that the decreased accumulation of MCLV in the protoplasts was due to the absence of V2 expression. These results revealed that MCLV-encoded V2 greatly enhances the level of MCLV DNA accumulation and is designated the replication enhancer protein of MCLV.
桑萎缩病毒（MCLV）在桑树上被发现，是 科 属的一个成员。MCLV 编码的 V2 蛋白的功能尚不清楚。在这里，构建了野生型 MCLV vII（MCLV）和两个 V2 突变型 MCLV vIIs 的 -介导的感染性克隆，包括 MCLV（V2 ORF 的起始密码子发生突变）和 MCLV（V2 ORF 序列的 5'-端部分缺失），以研究 V2 在体内和细胞水平上的作用。尽管这三个构建体（pCA-1.1MCLV、pCA-MCLV 和 pCA-MCLV）都能够系统地感染天然宿主桑树和实验性番茄植物，但与 MCLV 相比，MCLV 和 MCLV 基因组在这些宿主中的复制明显减少。同样，与 MCLV 相比，MCLV 和 MCLV 在 植物原生质体中的积累在 24 小时或 48 小时转染后显著降低。互补实验进一步证实，MCLV 在原生质体中的积累减少是由于 V2 表达缺失所致。这些结果表明，MCLV 编码的 V2 极大地增强了 MCLV DNA 积累的水平，被指定为 MCLV 的复制增强蛋白。
