Respiratory syncytial virus genome replication

Replication of the negative sense genomic RNA of the human respiratory syncytial virus (RSV) occurs through the positive sense intermediate, also known as antigenomic RNA. RNA synthesis is performed by the RNA-dependent RNA polymerase (RdRP) complex composed at a minimum of the L protein, which is the catalytic subunit of RdRP, and P protein. Protein M2-1 that acts as a processivity factor is described as a consitutive RdRP subunit by some and as an accessory RdRP subunit by other studies (reviewed in Fearns and Deval 2016). Replication of both genomic and antigenomic RNA depends on encapsidation by protein N, which has regions that interact with both protein P and protein L. Encapsidation protects genomic and antigenomic RNA from degradation as these RNAs do not possess the 5' cap and the poly(A) tail. Replication occurs after primary transcription. Accumulation of the protein M2-2 is responsible for the shift of RNA synthesis from transcription to replication through a mechanism that has not been fully elucidated (For review, refer to Collins and Melero 2011, Battles and McLellan 2019).

人类呼吸道合胞病毒（RSV）负链基因组RNA的复制过程通过正链中间体实现，亦称为抗原基因组RNA。RNA合成由RNA依赖性RNA聚合酶（RdRP）复合体执行，该复合体至少由L蛋白组成，L蛋白是RdRP的催化亚基，以及P蛋白。M2-1蛋白，作为过程性因子，部分研究将其描述为RdRP的组成性亚基，而其他研究则将其视为辅助性亚基（如Fearns和Deval 2016年综述）。基因组RNA和抗原基因组RNA的复制均依赖于由蛋白N介导的包膜化，蛋白N与蛋白P和蛋白L相互作用。包膜化保护基因组RNA和抗原基因组RNA免受降解，因为这些RNA不具备5'帽和poly(A)尾。复制过程在初级转录之后发生。M2-2蛋白的积累负责将RNA合成从转录阶段转移到复制阶段，其具体机制尚未完全阐明（参见Collins和Melero 2011年及Battles和Mclellan 2019年的综述）。