eIF4A在帽依赖和IRES介导的翻译起始中的作用

The role of eIF4A in cap-and IRES-DEPENDENT TRANSLATION Initiation

生物体内翻译起始机制分为两类:帽依赖性翻译起始和内部核糖体进入位点(internal ribosome entry sites,IRES)介导的翻译起始。真核生物的翻译起始为经典的帽依赖性翻译起始模型,而大多数正链RNA病毒选择依赖于IRES的翻译机制。真核翻译起始因子4A(eukaryotic initiation factor 4A,eIF4A)是DEAD-box RNA解旋酶家族的成员,具有依赖于RNA的ATP酶活性和RNA解旋酶活性,而e IF4A具体的解旋机制至今仍不清晰。同时,eIF4A与其他翻译因子有着复杂而紧密的联系,在帽依赖性与IRES介导的翻译起始过程中扮演着至关重要的角色。本文主要对eIF4A的功能、结构以及eIF4A在帽依赖性与IRES介导的翻译起始过程中的机制作一综述。

In biological systems,there are two primary translation initiation mechanisms:cap-dependent translation initiation and internal ribosome entry sites(IRES)-mediated translation initiation.Cap-dependent translation initiation is the classical model in eukaryotic organisms,while most positive-strand RNA viruses employ an IRESdependent translation mechanism.The eukaryotic initiation factor 4A(eIF4A),a member of the DEAD-box RNA helicase family,features RNA-dependent ATPase and RNA helicase activities,yet the specific unwinding mechanism of eIF4A remains unclear.Additionally,eIF4A engages in complex and close interactions with other eukaryotic initiation factors,playing a key role in both cap-dependent and IRES-mediated translation initiation processes.This article primarily reviews the functions and structures of eIF4A,and the mechanisms of eIF4A in cap-dependent and IRES-mediated translation initiation.