Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia, 46001Valencia, Spain.
Escuela de Doctorado, Universidad Católica de Valencia, 46001Valencia, Spain.
Nucleic Acids Res. 2022 Feb 28;50(4):2287-2301. doi: 10.1093/nar/gkac061.
Subdomain 5BSL3.2 of hepatitis C virus RNA lies at the core of a network of distal RNA-RNA contacts that connect the 5' and 3' regions of the viral genome and regulate the translation and replication stages of the viral cycle. Using small-angle X-ray scattering and NMR spectroscopy experiments, we have determined at low resolution the structural models of this subdomain and its distal complex with domain 3'X, located at the 3'-terminus of the viral RNA chain. 5BSL3.2 adopts a characteristic 'L' shape in solution, whereas the 5BSL3.2-3'X distal complex forms a highly unusual 'Y'-shaped kissing junction that blocks the dimer linkage sequence of domain 3'X and promotes translation. The structure of this complex may impede an effective association of the viral polymerase with 5BSL3.2 and 3'X to start negative-strand RNA synthesis, contributing to explain the likely mechanism used by these sequences to regulate viral replication and translation. In addition, sequence and shape features of 5BSL3.2 are present in functional RNA motifs of flaviviruses, suggesting conserved regulatory processes within the Flaviviridae family.
丙型肝炎病毒 RNA 的 Subdomain 5BSL3.2 位于一个远程 RNA-RNA 接触网络的核心，该网络连接病毒基因组的 5'和 3'区域，并调节病毒周期的翻译和复制阶段。使用小角度 X 射线散射和 NMR 光谱实验，我们在低分辨率下确定了该亚域及其与位于病毒 RNA 链 3'末端的 3'X 结构域的远程复合物的结构模型。5BSL3.2 在溶液中采用特征性的“L”形，而 5BSL3.2-3'X 远程复合物形成一种非常不寻常的“Y”形 kissing junction，该 junction 阻止了 3'X 结构域的二聚体连接序列，并促进翻译。这种复合物的结构可能会阻碍病毒聚合酶与 5BSL3.2 和 3'X 的有效结合，从而开始负链 RNA 合成，这有助于解释这些序列用于调节病毒复制和翻译的可能机制。此外，5BSL3.2 的序列和形状特征存在于黄病毒的功能性 RNA 基序中，表明 Flaviviridae 家族内存在保守的调节过程。
