Yang Shen, Shan Tongling, Zhou Yanjun, Jiang Yifeng, Tong Wu, Liu Fei, Wen Feng, Zhang Qingzhan, Tong Guangzhi
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses,Yangzhou 225009, China.
Dev Comp Immunol. 2014 Dec;47(2):234-46. doi: 10.1016/j.dci.2014.07.024. Epub 2014 Aug 5.
The sterile alpha motif and HD domain 1 (SAMHD1) protein is a novel innate immunity restriction factor that inhibits HIV-1 infection in myeloid cells. Here, we cloned the full-length SAMHD1 complementary DNA (cDNA) from porcine peripheral blood lymphocytes. The porcine SAMHD1 cDNA was of 3951 bp with an open reading frame of 1884 bp, encoding a polypeptide of 627 amino acids. Porcine SAMHD1 mRNA was detected in all swine tissues examined, with the higher expression in the tonsil, lung, liver, and lymph node tissues. The SAMHD1 protein was localized to the nucleus. Overexpression of SAMHD1 blocked the proliferation of HuN4, a highly pathogenic strain of porcine reproductive and respiratory syndrome virus (HP-PRRSV), in MARC-145 cells, by inhibiting the synthesis of the HuN4 complement RNA. The antiviral effects of the simian SAMHD1 protein were nearly equivalent to those of porcine SAMHD1 in the HuN4-infected MARC-145 cells. Phosphorylation analysis of SAMHD1 showed that overexpressed SAMHD1 protein was in primarily an unphosphorylated state. SAMHD1 overexpression increased the transcript abundance of IFN-stimulated genes ISG15 and ISG56. The mRNA levels of SAMHD1 and ISGs were significantly increased in porcine alveolar macrophages infected with HP-PRRSV. SAMHD1 protein level was also elevated, and the protein was not phosphorylated during infection. Collectively, our data indicate that SAMHDI inhibits HP-PRRSV proliferation through inhibiting the replication of HP-PRRSV. SAMHD1 might be the protein participating in the IFN signaling and is thus an important immunoregulatory protein in innate immunity.
无菌α基序和HD结构域1（SAMHD1）蛋白是一种新型的固有免疫限制因子，可抑制髓系细胞中的HIV-1感染。在此，我们从猪外周血淋巴细胞中克隆了全长SAMHD1互补DNA（cDNA）。猪SAMHD1 cDNA为3951 bp，开放阅读框为1884 bp，编码一个627个氨基酸的多肽。在所检测的所有猪组织中均检测到猪SAMHD1 mRNA，在扁桃体、肺、肝和淋巴结组织中表达较高。SAMHD1蛋白定位于细胞核。SAMHD1的过表达通过抑制HuN4互补RNA的合成，阻断了高致病性猪繁殖与呼吸综合征病毒（HP-PRRSV）HuN4株在MARC-145细胞中的增殖。在感染HuN4的MARC-145细胞中，猿猴SAMHD1蛋白的抗病毒作用与猪SAMHD1的作用几乎相当。SAMHD1的磷酸化分析表明，过表达的SAMHD1蛋白主要处于未磷酸化状态。SAMHD1过表达增加了干扰素刺激基因ISG15和ISG56的转录丰度。在感染HP-PRRSV的猪肺泡巨噬细胞中，SAMHD1和ISG的mRNA水平显著升高。SAMHD1蛋白水平也升高，且在感染期间该蛋白未被磷酸化。总体而言，我们的数据表明SAMHDI通过抑制HP-PRRSV的复制来抑制其增殖。SAMHD1可能是参与干扰素信号传导的蛋白，因此是固有免疫中一种重要的免疫调节蛋白。
