RNA binding protein TIAR modulates HBV replication by tipping the balance of pgRNA translation

作者：Ting Zhang, Huiling Zheng, Danjuan Lu, Guiwen Guan, Deyao Li, Jing Zhang, Shuhong Liu, Jingmin Zhao, Ju‐Tao Guo, Fengmin Lu, Xiangmei Chen · 发表于：Signal Transduction and Targeted Therapy · 年份：2023 · DOI：10.1038/s41392-023-01573-7 · 被引用次数：19 · 研究领域：Hepatitis B Virus Studies、Hepatitis C virus research、RNA Interference and Gene Delivery

The pregenomic RNA (pgRNA) of hepatitis B virus (HBV) serves not only as a bicistronic message RNA to translate core protein (Cp) and DNA polymerase (Pol), but also as the template for reverse transcriptional replication of viral DNA upon packaging into nucleocapsid. Although it is well known that pgRNA translates much more Cp than Pol, the molecular mechanism underlying the regulation of Cp and Pol translation efficiency from pgRNA remains elusive. In this study, we systematically profiled HBV nucleocapsid- and pgRNA-associated cellular proteins by proteomic analysis and identified TIA-1-related protein (TIAR) as a novel cellular protein that binds pgRNA and promotes HBV DNA replication. Interestingly, loss- and gain-of-function genetic analyses showed that manipulation of TIAR expression did not alter the levels of HBV transcripts nor the secretion of HBsAg and HBeAg in human hepatoma cells supporting HBV replication. However, Ribo-seq and PRM-based mass spectrometry analyses demonstrated that TIAR increased the translation of Pol but decreased the translation of Cp from pgRNA. RNA immunoprecipitation (RIP) and pulldown assays further revealed that TIAR directly binds pgRNA at the 5' stem-loop (ε). Moreover, HBV replication or Cp expression induced the increased expression and redistribution of TIAR from the nucleus to the cytoplasm of hepatocytes. Our results thus imply that TIAR is a novel cellular factor that regulates HBV replication by binding to the 5' ε structure of ...