State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
Dev Comp Immunol. 2023 Nov;148:104915. doi: 10.1016/j.dci.2023.104915. Epub 2023 Aug 14.
Mammalian heterogeneous nuclear ribonucleoproteins M (hnRNPM) is a critical splicing regulatory protein that has been reported to negatively regulate the RLR signaling pathway by impairing the binding of RIG-I and MDA5 to viral RNA. To explore the role of hnRNPM in the antiviral innate immune response in teleost fish, the hnRNPM homologue of triploid fish (3nhnRNPM) has been cloned and identified in this paper. The CDS of 3nhnRNPM gene is composed of 2016 nucleotides and encodes 671 amino acids. 3nhnRNPM migrated around 71 kDa in immunoblotting assay and was mainly detected in the nucleus in nucleo-cytoplasmic separation assay and immunofluorescent staining test. When 3nhnRNPM and 3nIRF7 were co-expressed in EPC cells, 3nhnRNPM significantly reduced the 3nIRF7-induced interferon (IFN) promoter transcription. Correspondingly, the mRNA levels of the SVCV-M, -N, -P, and -G genes were noteworthily enhanced, but the transcription levels of epcIFNφ1, epcMx1, epcPKR, and epcISG15 were dramatically decreased. Additionally, the knockdown of 3nhnRNPM resulted in restricted SVCV replication and enhanced host cell antiviral activity. Furthermore, the association between 3nhnRNPM and 3nIRF7 has been identified by the co-immunoprecipitation assay. In addition, we found that 3nIRF7 was detained in the nucleus when co-expressed with 3nhnRNPM. To sum up, our data supported the conclusion that 3nhnRNPM suppressed 3nIRF7-mediated IFN signaling in the antiviral innate immunity.
哺乳动物异质核核糖核蛋白 M（hnRNPM）是一种关键的剪接调控蛋白，据报道，它通过损害 RIG-I 和 MDA5 与病毒 RNA 的结合来负调控 RLR 信号通路。为了探索 hnRNPM 在硬骨鱼类抗病毒先天免疫反应中的作用，本文克隆并鉴定了三倍体鱼类的 hnRNPM 同源物（3nhnRNPM）。3nhnRNPM 基因的 CDS 由 2016 个核苷酸组成，编码 671 个氨基酸。免疫印迹分析显示，3nhnRNPM 迁移约 71 kDa，核质分离分析和免疫荧光染色试验表明，3nhnRNPM 主要定位于细胞核。当 3nhnRNPM 和 3nIRF7 在 EPC 细胞中共表达时，3nhnRNPM 显著降低了 3nIRF7 诱导的干扰素（IFN）启动子转录。相应地，SVCV-M、-N、-P 和 -G 基因的 mRNA 水平显著增强，但 epcIFNφ1、epcMx1、epcPKR 和 epcISG15 的转录水平显著降低。此外，3nhnRNPM 的敲低导致 SVCV 复制受到限制，宿主细胞抗病毒活性增强。此外，通过共免疫沉淀试验证实了 3nhnRNPM 与 3nIRF7 之间的关联。此外，我们发现当与 3nhnRNPM 共表达时，3nIRF7 被滞留在细胞核内。总之，我们的数据支持了 3nhnRNPM 抑制抗病毒先天免疫中 3nIRF7 介导的 IFN 信号转导的结论。
