Translation of Structural Proteins

This COVID-19 pathway has been created by a combination of computational inference from SARS-CoV-1 data (https://reactome.org/documentation/inferred-events) and manual curation, as described in the summation for the overall SARS-CoV-2 infection pathway.<br><br>Virus mRNA is translated according to the ribosomal scanning model. It is capped and polyadenylated, with regions of nontranslated sequences on both the 5' and 3' ends. Structural proteins are encoded after the polymerase/replicase genes by mRNAs 2 (Spike protein), 3, 4 (Envelope protein), 5 (Membrane protein), and 9. mRNA 3 and 9 are bicistronic, the proteins 3a and 9a (Nucleocapsid protein) having functions in virus assembly and structure. Translation happens in the ER with the exception of 9a which is translated by cytosolic free ribosomes (Fung and Liu, 2019).

本COVID-19通路系通过结合从SARS-CoV-1数据中进行的计算推理（https://reactome.org/documentation/inferred-events）以及人工编纂而成，具体编纂过程详见于整体SARS-CoV-2感染通路概要。<br><br>病毒mRNA的翻译遵循核糖体扫描模型。其5'和3'端均存在非翻译序列，并带有帽状结构和多聚腺苷酸化。结构蛋白的编码位于聚合酶/复制酶基因之后，由mRNA 2（刺突蛋白）、3、4（包膜蛋白）、5（膜蛋白）和9进行编码。mRNA 3和9为双顺反子，其3a和9a蛋白（核衣壳蛋白）在病毒组装和结构中发挥功能。翻译过程主要在糙面内质网中进行，9a蛋白的翻译则由细胞质游离核糖体完成（Fung和Liu，2019）。