Interferon-dependent R-loop Induction by Zika Virus Contributes to Growth Attenuation [ZIKV_Bruseq]

Zika virus (ZIKV) infection in human neural progenitors triggers DNA damage and activates DNA damage response, leading to cell cycle arrest that can retard brain development. Here we link the ZIKV- induced S phase arrest to replication fork stalling and R-loop induction. DRIP-seq reveals that ZIKV infection induces R-loops at specific loci strongly enriched in the interferon-stimulated genes (ISGs). Bru-seq results further indicate that nascent ISGs transcripts are prone to R-loop induction upon infection. Knockout of interferon receptor eliminated the R-loops on ISGs and partially rescued S phase arrest in infected cells. And overexpression of RNaseH1 reduced ZIKV-mediated DNA damage and cell cycle arrest. We conclude that unscheduled expression of ISGs induced by ZIKV alters R-loop homeostasis and perturbs replication fork progression, leading to fork stalling and eventually DNA damage. IFN- dependent R-loop induction represents a previously unknown, nucleic acid-based mechanism for cell cycle arrest. human glioblastoma SNB-19 cells were treated by MR and PR ZIKV virus and subjuct for Bru-seq, untreated Mock control were used for comparison

寨卡病毒（Zika virus, ZIKV）感染人类神经前体细胞可引发DNA损伤并激活DNA损伤应答通路，进而导致细胞周期阻滞，延缓大脑发育。本研究将寨卡病毒诱导的S期阻滞与复制叉停滞及R环（R-loop）形成相关联。DRIP-seq测序结果显示，寨卡病毒感染可在干扰素刺激基因（interferon-stimulated genes, ISGs）高度富集的特定基因组位点诱导R环形成。Bru-seq测序结果进一步表明，感染状态下新生的干扰素刺激基因转录本易于发生R环形成。敲除干扰素受体可消除干扰素刺激基因位点上的R环，并部分挽救感染细胞的S期阻滞表型。而过表达RNaseH1则可减轻寨卡病毒介导的DNA损伤与细胞周期阻滞。本研究得出结论：寨卡病毒诱导的干扰素刺激基因异常表达会改变R环稳态，干扰复制叉行进进程，最终导致复制叉停滞与DNA损伤。依赖于干扰素的R环诱导代表了一种此前未被发现的、基于核酸的细胞周期阻滞机制。本研究将人类胶质母细胞瘤SNB-19细胞分别用MR和PR株寨卡病毒处理并开展Bru-seq测序，同时以未感染的Mock（空白对照）作为对照进行对比分析。