Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Bond Life Sciences Center, Columbia, Missouri, USA.
Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Bond Life Sciences Center, Columbia, Missouri, USA
J Virol. 2019 Jan 4;93(2). doi: 10.1128/JVI.01530-18. Print 2019 Jan 15.
The NP1 protein of minute virus of canines (MVC) governs production of the viral capsid proteins via its role in pre-mRNA processing. NP1 suppresses polyadenylation and cleavage at its internal site, termed the proximal polyadenylation (pA)p site, to allow accumulation of RNAs that extend into the capsid gene, and it enhances splicing of the upstream adjacent third intron, which is necessary to properly enter the capsid protein open reading frame. We find the (pA)p region to be complex. It contains redundant classical -acting signals necessary for the cleavage and polyadenylation reaction and splicing of the adjacent upstream third intron, as well as regions outside the classical motifs that are necessary for responding to NP1. NP1, but not processing mutants of NP1, bound to MVC RNA directly. The cellular RNA processing factor CPSF6 interacted with NP1 in transfected cells and participated with NP1 to modulate its effects. These experiments further characterize the role of NP1 in parvovirus gene expression. The are small nonenveloped icosahedral viruses that are important pathogens in many animal species, including humans. Unlike other parvoviruses, the bocavirus genus controls expression of its capsid proteins via alternative RNA processing, by both suppressing polyadenylation at an internal site, termed the proximal polyadenylation (pA)p site, and by facilitating splicing of an upstream adjacent intron. This regulation is mediated by a small genus-specific protein, NP1. Understanding the -acting targets of NP1, as well as the cellular factors with which it interacts, is necessary to more clearly understand this unique mode of parvovirus gene expression.
犬细小病毒 NP1 蛋白通过在 pre-mRNA 加工中的作用来控制病毒衣壳蛋白的产生。NP1 通过抑制其内部位点的多聚腺苷酸化和切割，即近端多聚腺苷酸化（pA）p 位点，来允许延长到衣壳基因的 RNA 积累，并且它增强了上游相邻的第三个内含子的剪接，这对于正确进入衣壳蛋白开放阅读框是必要的。我们发现（pA）p 区域很复杂。它包含冗余的经典作用信号，这些信号对于切割和多聚腺苷酸化反应以及相邻上游第三个内含子的剪接是必要的，以及经典基序之外的区域，这些区域对于响应 NP1 是必要的。NP1，但不是 NP1 的加工突变体，直接与 MVC RNA 结合。细胞 RNA 加工因子 CPSF6 在转染细胞中与 NP1 相互作用，并与 NP1 一起参与调节其作用。这些实验进一步描述了 NP1 在细小病毒基因表达中的作用。细小病毒是小型无包膜二十面体病毒，是许多动物物种（包括人类）的重要病原体。与其他细小病毒不同，博卡病毒属通过替代 RNA 加工来控制其衣壳蛋白的表达，通过抑制内部位点的多聚腺苷酸化，即近端多聚腺苷酸化（pA）p 位点，并通过促进上游相邻内含子的剪接。这种调节是由一种小的属特异性蛋白 NP1 介导的。了解 NP1 的作用靶点，以及与它相互作用的细胞因子，对于更清楚地了解这种独特的细小病毒基因表达模式是必要的。
