Li Zhenhui, Luo Qingbin, Xu Haiping, Zheng Ming, Abdalla Bahareldin Ali, Feng Min, Cai Bolin, Zhang Xiaocui, Nie Qinghua, Zhang Xiquan
Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural UniversityGuangzhou, China; Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding and the Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of AgricultureGuangzhou, China.
Front Cell Infect Microbiol. 2017 Jan 30;7:17. doi: 10.3389/fcimb.2017.00017. eCollection 2017.
Avian leukosis virus subgroup J (ALV-J) is an oncogenic retrovirus that has a similar replication cycle to multiple viruses and therefore can be used as a model system for viral entry into host cells. However, there are few reports on the genes or microRNAs (miRNAs) that are responsible for the replication of ALV-J. Our previous miRNA and RNA sequencing data showed that the expression of miR-34b-5p was significantly upregulated in ALV-J-infected chicken spleens compared to non-infected chicken spleens, but melanoma differentiation-associated gene 5 () had the opposite expression pattern. In this study, a dual-luciferase reporter assay showed that is a direct target of miR-34b-5p. , overexpression of miR-34b-5p accelerated the proliferation of ALV-J-infected cells by inducing the progression from G2 to S phase and it promoted cell migration. Ectopic expression of inhibited ALV-J-infected cell proliferation, the cell cycle and cell migration, and knockdown of promoted proliferation, the cell cycle and migration. In addition, during ALV-J infections, can detect virus invasion and it triggers the MDA5 signaling pathway. overexpression can activate the MDA5 signaling pathway, and thus it can inhibit the mRNA and protein expression of the ALV-J gene and it can suppress virion secretion. In contrast, in response to the knockdown of by small interfering RNA (siRNA) or an miR-34b-5p mimic, genes in the MDA5 signaling pathway were significantly downregulated ( < 0.05), but the mRNA and protein expression of ALV-J and the sample-to-positive ratio of virion in the supernatants were increased. This indicates that miR-34b-5p is able to trigger the MDA5 signaling pathway and affect ALV-J infections. Together, these results suggest that miR-34b-5p targets to accelerate the proliferation and migration of ALV-J-infected cells, and it promotes ALV-J replication, via the MDA5 signaling pathway.
禽白血病病毒J亚群（ALV-J）是一种致癌逆转录病毒，其复制周期与多种病毒相似，因此可作为病毒进入宿主细胞的模型系统。然而，关于负责ALV-J复制的基因或微小RNA（miRNA）的报道很少。我们之前的miRNA和RNA测序数据显示，与未感染ALV-J的鸡脾脏相比，miR-34b-5p在感染ALV-J的鸡脾脏中的表达显著上调，但黑色素瘤分化相关基因5（MDA5）具有相反的表达模式。在本研究中，双荧光素酶报告基因检测表明MDA5是miR-34b-5p的直接靶标。此外，miR-34b-5p的过表达通过诱导细胞从G2期进入S期加速了ALV-J感染细胞的增殖，并促进了细胞迁移。MDA5的异位表达抑制了ALV-J感染细胞的增殖、细胞周期进程和细胞迁移，而敲低MDA5则促进了细胞增殖、细胞周期进程和迁移。此外，在ALV-J感染期间，MDA5能够检测到病毒入侵并触发MDA5信号通路。MDA5的过表达可以激活MDA5信号通路，从而抑制ALV-J gag基因的mRNA和蛋白表达，并抑制病毒粒子的分泌。相反，用小干扰RNA（siRNA）或miR-34b-5p模拟物敲低MDA5后，MDA5信号通路中的基因显著下调（P<0.05），但ALV-J gag的mRNA和蛋白表达以及上清液中病毒粒子的样本与阳性比率增加。这表明miR-34b-5p能够触发MDA5信号通路并影响ALV-J感染。总之，这些结果表明，miR-34b-5p靶向MDA5以加速ALV-J感染细胞的增殖和迁移，并通过MDA5信号通路促进ALV-J复制。
