Saito Mariko, Tsukagoshi Hiroyuki, Ishigaki Hirotaka, Aso Jumpei, Ishii Haruyuki, Okayama Kaori, Ryo Akihide, Ishioka Taisei, Kuroda Makoto, Saruki Nobuhiro, Katayama Kazuhiko, Kimura Hirokazu
Gunma Prefectural Institute of Public Health and Environmental Sciences, 378 Kamioki-machi, Maebashi-shi, Gunma 371-0052, Japan.
Department of Health Science, Gunma Paz University Graduate School of Health Sciences, 1-7-1 Tonyamachi, Takasaki-shi, Gunma 370-0006, Japan.
Heliyon. 2020 May 3;6(5):e03835. doi: 10.1016/j.heliyon.2020.e03835. eCollection 2020 May.
Norovirus GII.3 has been suggested to be a prevalent genotype in patients with acute gastroenteritis. However, the genetic properties of the region encoding the major GII.3 antigen remain unclear. Here, we performed molecular evolutionary analyses of the GII.3 region detected in various countries. We performed time-scaled phylogenetic analyses, selective pressure analyses, phylogenetic distance analyses, and conformational epitope analyses. The time-scaled phylogenetic tree showed that an ancestor of the GII.3 region diverged from the common ancestors of the GII.6, GII.11, GII.18, and GII.19 approximately 70 years ago with relatively low divergence. The evolutionary rate of the GII.3 region was rapid (4.82 × 10 substitutions/site/year). Furthermore, one positive site and many negative selection sites were observed in the capsid protein. These results suggest that the GII.3 region rapidly evolved with antigenic variations.
诺如病毒GII.3被认为是急性肠胃炎患者中一种流行的基因型。然而，编码主要GII.3抗原的区域的遗传特性仍不清楚。在此，我们对在各个国家检测到的GII.3区域进行了分子进化分析。我们进行了时间尺度系统发育分析、选择压力分析、系统发育距离分析和构象表位分析。时间尺度系统发育树显示，GII.3区域的一个祖先大约在70年前从GII.6、GII.11、GII.18和GII.19的共同祖先中分化出来，分化程度相对较低。GII.3区域的进化速率很快（4.82×10个替换/位点/年）。此外，在衣壳蛋白中观察到一个正选择位点和许多负选择位点。这些结果表明，GII.3区域随着抗原变异而快速进化。
