Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
Virus Res. 2020 Jul 2;283:197960. doi: 10.1016/j.virusres.2020.197960. Epub 2020 Apr 11.
The G-quadruplex (GQ) motifs have recently been gaining prominence because of their role as gene cis-regulatory elements in a variety of organisms and as potential druggable targets for anti-cancer therapy and ageing. Several studies have demonstrated the existence of GQs in the genomes of emerging and re-emerging human pathogens, such as hepatitis virus, herpesviruses, Ebola virus, Zika virus and Nipah virus. Human Adenovirus (HAdV) exhibits a large number of clinical manifestations especially infecting the children and the immunocompromised patients. Moreover, the HAdV-based vectors have been widely used to deliver foreign DNAs to cells in gene therapy. However, the DNA secondary structural elements in AdV-based vectors could significantly determine the gene delivery efficacy of the vectors. In this study, using a combination of whole genome sequence analysis, biochemical, biophysical and interaction assays, we revealed fifteen putative GQs that are conserved across the different species of HAdV. We further showed that the GQs are embedded in the sequences of essential viral genes, namely E1B, E2B, and L3 genes (among others), which are involved in the early and late stages of the viral life cycle. Notably, Braco-19 (a well-known GQ binding ligand) interacted specifically with the HAdV GQs and increased their stability and further blocked the HAdV multiplication in human cells. Taken together, our data strongly supported the existence of G-quadruplex structures in the HAdV genome that affect the virus multiplication and posit that such structures may influence the efficacy of the gene-delivery vectors or even the HAdV virus life-cycle.
G-四链体 (GQ) 结构近年来备受关注，因为它们在多种生物体中作为基因顺式调控元件发挥作用，并可能成为抗癌治疗和衰老的潜在药物靶点。多项研究表明，GQ 存在于新兴和重现的人类病原体的基因组中，如肝炎病毒、疱疹病毒、埃博拉病毒、寨卡病毒和尼帕病毒。人类腺病毒 (HAdV) 表现出多种临床表现，特别是感染儿童和免疫功能低下的患者。此外，基于 HAdV 的载体已被广泛用于将外源 DNA 递送至基因治疗中的细胞。然而，AdV 载体中的 DNA 二级结构元件会显著影响载体的基因传递效率。在这项研究中，我们通过全基因组序列分析、生化、生物物理和相互作用测定的组合，揭示了在不同 HAdV 物种中保守的十五个推定 GQ。我们进一步表明，GQ 嵌入到病毒必需基因（包括 E1B、E2B 和 L3 基因等）的序列中，这些基因参与病毒生命周期的早期和晚期。值得注意的是，Braco-19（一种众所周知的 GQ 结合配体）特异性地与 HAdV GQ 相互作用，增加了它们的稳定性，并进一步阻断了 HAdV 在人细胞中的增殖。总之，我们的数据强烈支持 HAdV 基因组中存在影响病毒增殖的 G-四链体结构，并表明这些结构可能影响基因传递载体的疗效，甚至影响 HAdV 病毒的生命周期。
