Key Laboratory of Veterinary Biological Products, College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, 450046, China.
College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, China.
Virol J. 2022 May 15;19(1):82. doi: 10.1186/s12985-022-01811-4.
Heterogeneous nuclear ribonucleoprotein (HnRNP) F is a member of HnRNP family proteins that participate in splicing of cellular newly synthesized mRNAs by specifically recognizing tandem guanine-tracts (G-tracts) RNA sequences. Whether HnRNP F could recognize viral-derived tandem G-tracts and affect virus replication remain poorly defined.
The effect of HnRNP F on porcine reproductive and respiratory syndrome virus (PRRSV) propagation was evaluated by real-time PCR, western blotting, and plaque-forming unit assay. The association between HnRNP F and PRRSV guanine-rich segments (GRS) were analyzed by RNA pulldown and RNA immunoprecipitation. The expression pattern of HnRNP F was investigated by western blotting and nuclear and cytoplasmic fractionation.
Knockdown of endogenous HnRNP F effectively blocks the synthesis of viral RNA and nucleocapsid (N) protein. Conversely, overexpression of porcine HnRNP F has the opposite effect. Moreover, RNA pulldown and RNA immunoprecipitation assays reveal that the qRMM1 and qRRM2 domains of HnRNP F recognize the GRS in PRRSV antigenomic RNA. Finally, HnRNP F is redistributed into the cytoplasm and forms a complex with guanine-quadruplex (G4) helicase DHX36 during PRRSV infection.
These findings elucidate the potential functions of HnRNP F in regulating the proliferation of PRRSV and contribute to a better molecular understanding of host-PRRSV interactions.
异质核核糖核蛋白（HnRNP）F 是 HnRNP 家族蛋白的成员，通过特异性识别串联鸟嘌呤（G）-tracts（G- tracts）RNA 序列，参与细胞新合成的 mRNA 的剪接。HnRNP F 是否能够识别病毒衍生的串联 G- tracts 并影响病毒复制尚不清楚。
通过实时 PCR、western blot 和噬斑形成单位测定评估 HnRNP F 对猪繁殖与呼吸综合征病毒（PRRSV）增殖的影响。通过 RNA 下拉和 RNA 免疫沉淀分析 HnRNP F 与 PRRSV 鸟嘌呤丰富片段（GRS）的关联。通过 western blot 和核质分离分析 HnRNP F 的表达模式。
内源性 HnRNP F 的敲低有效地阻断了病毒 RNA 和核衣壳（N）蛋白的合成。相反，猪 HnRNP F 的过表达则有相反的效果。此外，RNA 下拉和 RNA 免疫沉淀试验显示，HnRNP F 的 qRMM1 和 qRRM2 结构域识别 PRRSV 抗原基因组 RNA 中的 GRS。最后，HnRNP F 在 PRRSV 感染期间重新分布到细胞质中，并与鸟嘌呤-四链体（G4）解旋酶 DHX36 形成复合物。
这些发现阐明了 HnRNP F 在调节 PRRSV 增殖中的潜在功能，有助于更好地理解宿主-PRRSV 相互作用的分子机制。
