Institute of Chemical Biology and Fundamental Medicine SB RAS, 630090 Novosibirsk, Russia.
Viruses. 2020 May 22;12(5):573. doi: 10.3390/v12050573.
A new crAss-like genome encoding diversity-generating retroelement (DGR) was found in the fecal virome of a healthy volunteer. The genome of the phage referred to as the crAssphage LMMB, belonged to the candidate of the AlphacrAssvirinae subfamily. The DGR-cassette of the crAssphage LMMB contained all the essential elements: the gene encoding reverse transcriptase (RT), the target gene (TG) encoding the tail-collar fiber protein, and variable and template repeats (VR and TR) with IMH (initiation of mutagenic homing) and IMH* sequences at the 3'-end of the VR and TR, respectively. Architecture of the DGR-cassette was TG-VR(IMH)-TR(IMH*)-RT and an accessory variable determinant (avd) was absent from the cassette. Analysis of 91 genomes and genome fragments from of the AlphacrAssvirinae showed that 15 (16%) of the genomes had DGRs with the same architecture as the crAssphage LMMB, while 66 of the genomes contained incomplete DGR-cassettes or some elements of the DGR.
在一位健康志愿者的粪便病毒组中发现了一个新的 crAss 样基因组，该基因组能够编码多样性产生反转录转座子（DGR）。这种噬菌体的基因组被称为 crAssphage LMMB，属于 AlphacrAssvirinae 亚科的候选者。crAssphage LMMB 的 DGR 盒包含所有必需元件：编码逆转录酶（RT）的基因、编码尾部套环纤维蛋白的靶基因（TG），以及具有 IMH（诱变同源起始）序列的可变和模板重复（VR 和 TR），以及 VR 和 TR 3'端的 IMH序列。DGR 盒的结构为 TG-VR(IMH)-TR(IMH)-RT，并且盒中不存在辅助可变决定簇（avd）。对来自 AlphacrAssvirinae 的 91 个基因组和基因组片段的分析表明，15 个（16%）基因组具有与 crAssphage LMMB 相同结构的 DGR，而 66 个基因组包含不完整的 DGR 盒或 DGR 的某些元件。
