Ternovoi Vladimir A, Gladysheva Anastasia V, Ponomareva Eugenia P, Mikryukova Tamara P, Protopopova Elena V, Shvalov Alexander N, Konovalova Svetlana N, Chausov Eugene V, Loktev Valery B
Department of Molecular Virology for Flaviviruses and Viral Hepatitis, State Research Center for Virology and Biotechnology "Vector", Koltsovo, Novosibirsk Region, 630559, Russia.
Novosibirsk State University, Novosibirsk, 630090, Russia.
Virus Genes. 2019 Aug;55(4):448-457. doi: 10.1007/s11262-019-01672-0. Epub 2019 May 20.
Tick-borne encephalitis viruses (TBEVs) are usually divided into three major subtypes: European (TBEV-Eu), Siberian (TBEV-Sib) and Far Eastern (TBEV-FE). The TBEV-Eu strains have the longest genomes, and TBEV-FE strains have the smallest genomes. Changes in the variable region of the untranslated region (V3' UTR) play a major role in determining the viral genome length. Analyses of the 3' UTRs of the different subtypes of TBEV have revealed significant changes in the secondary structures of the V3' UTR of TBEV. More complex secondary structures of the V3' UTR regions are typical for TBEV-Eu. The Siberian strain Tomsk-PT122 was isolated from birds and has an unusual 3' UTR. Several short fragment (24-26 nucleotides) insertions derived from the viral E (2) and NS4a (1) genes have been found in the V3' UTR of Tomsk-PT122. Additionally, the length of the V3' UTR increases from 21 to 37 nucleotides during passages of the C11-13 strain of TBEV-Sib into PEK, 293 and Neuro-2a cells. The elongation of the V3' UTRs of Tomsk-PT122 and C11-13 is the first direct evidence of an intragenomic 3' UTR modification (insertion) for TBEV. Thus, the obtained results suggest that changing the length of the V3' UTR in the genome is typical for different TBEV subtypes and can play an essential role in effective TBEV replication in different host cells.
蜱传脑炎病毒（TBEV）通常分为三个主要亚型：欧洲型（TBEV-Eu）、西伯利亚型（TBEV-Sib）和远东型（TBEV-FE）。TBEV-Eu毒株的基因组最长，而TBEV-FE毒株的基因组最小。非翻译区可变区（V3'UTR）的变化在决定病毒基因组长度方面起主要作用。对TBEV不同亚型的3'UTR分析揭示了TBEV的V3'UTR二级结构的显著变化。V3'UTR区域更复杂的二级结构是TBEV-Eu的典型特征。西伯利亚毒株托木斯克-PT122是从鸟类中分离出来的，具有不寻常的3'UTR。在托木斯克-PT122的V3'UTR中发现了几个源自病毒E（2）和NS4a（1）基因的短片段（24-26个核苷酸）插入。此外，在TBEV-Sib的C11-13毒株传代至PEK、293和Neuro-2a细胞的过程中，V3'UTR的长度从21个核苷酸增加到37个核苷酸。托木斯克-PT122和C11-13的V3'UTR延长是TBEV基因组内3'UTR修饰（插入）的首个直接证据。因此，所得结果表明，基因组中V3'UTR长度的改变是不同TBEV亚型的典型特征，并且可能在TBEV在不同宿主细胞中的有效复制中起重要作用。
