Oliveira Graziele P, de Aquino Isabella L M, Luiz Ana P M F, Abrahão Jônatas S
Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
Front Microbiol. 2018 May 23;9:1041. doi: 10.3389/fmicb.2018.01041. eCollection 2018.
Putative promoter motifs have been described in viruses belonging to the nucleocytoplasmic large DNA viruses (NCLDVs) group; however, few studies have been conducted to search for promoter sequences in newly discovered amoebal giant viruses. Faustovirus and kaumoebavirus are two -related giant viruses belonging to the NCLDVs group. The phylogenetic relationships among these viruses led us to investigate if the promoter regions previously identified in the asfarvirus genome could be shared by its amoebal virus relatives. Previous studies demonstrated the role of A/T-rich motifs as promoters of asfarvirus. In this study, we reinforce the importance of A/T rich motifs in asfarvirus and show that the TATTT and TATATA motifs are also shared in abundance by faustovirus and kaumoebavirus. Here, we demonstrate that TATTT and TATATA are mostly present in faustovirus and kaumoebavirus genomic intergenic regions (IRs) and that they are widely distributed at 0 to -100 bp upstream to the start codons. We observed that putative promoter motifs are present as one to dozens of repetitions in IRs of faustovirus, kaumoebavirus, and asfarvirus, which is similar to that described previously for marseilleviruses. Furthermore, the motifs were found in most of the upstream regions of the core genes of faustovirus, kaumoebavirus, and asfarvirus, which suggests that the motifs could already be present in the ancestor of these viruses before the irradiation of this group. Our work provides an in-depth analysis of the putative promoter motifs present in asfarvirus, kaumoebavirus, and faustovirus, which reinforces the relationship among these viruses.
在属于核质大DNA病毒（NCLDVs）组的病毒中，已描述了推定的启动子基序；然而，针对新发现的变形虫巨型病毒寻找启动子序列的研究却很少。法斯托病毒和考莫埃巴病毒是属于NCLDVs组的两种相关巨型病毒。这些病毒之间的系统发育关系促使我们研究先前在阿斯法病毒基因组中鉴定出的启动子区域是否也为其变形虫病毒亲属所共有。先前的研究证明了富含A/T的基序作为阿斯法病毒启动子的作用。在本研究中，我们强化了富含A/T基序在阿斯法病毒中的重要性，并表明TATTT和TATATA基序在法斯托病毒和考莫埃巴病毒中也大量存在。在此，我们证明TATTT和TATATA主要存在于法斯托病毒和考莫埃巴病毒的基因组基因间隔区（IRs）中，并且它们广泛分布在起始密码子上游0至 -100 bp处。我们观察到，推定的启动子基序在法斯托病毒、考莫埃巴病毒和阿斯法病毒的IRs中以1至数十个重复的形式存在，这与先前对马赛病毒的描述相似。此外，在法斯托病毒、考莫埃巴病毒和阿斯法病毒核心基因的大多数上游区域都发现了这些基序，这表明在该病毒组辐射之前，这些基序可能已存在于这些病毒的共同祖先中。我们的工作对阿斯法病毒、考莫埃巴病毒和法斯托病毒中存在的推定启动子基序进行了深入分析，强化了这些病毒之间的关系。
