Development of a replicon cell line-based high throughput antiviral assay for screening inhibitors of Zika virus

Zika virus (ZIKV) is an important emerging human pathogen associated with microcephaly, Guillain-Barre syndrome and meningoencephalitis. Developing rapid and reliable HTS assay is important for ZIKV drug discovery. Here, we constructed a dicistronic ZIKV replicon (ZIKV-Pac-Rluc-Rep) that contained the Renilla luciferase (Rluc) reporter gene separated from the puromycin N-acetyl-transferase (Pac) selectable marker by a short peptide cleavage site. A clonal replicon cell line stably expressing high level of ZIKV replicon was established by selection with puromycin. By optimizing cell number, compound concentration and incubation time, a robust replicon cell-based HTS assay was developed with a calculated Z' value of > 0.5. The fully optimized assay was further validated using several known flavivirus replication inhibitors. Altogether, the replicon cell-based HTS assay developed in this study will facilitate the discovery of antiviral compounds against ZIKV.