無義介導的mRNA降解(nonsense-mediated mRNA decay，NMD）作為真核細胞中重要RNA監控機制，識別並降解開放閱讀框中含有提前終止密碼子（premature termination codon，PTC）的mRNA，以避免因截短的蛋白產物積累對細胞造成毒害. NMD還調控正常生理基因的表達，暗示其在真核細胞中扮演重要角色. NMD途徑的關鍵是PTC的識別。NMD通常由NMD因子UPF1（up-frameshift）等被招募至含PTC的mRNA上，藉助這些因子組裝形成“功能複合體”並激活降解.但目前對於PTC識別後的過程仍認識有限。
基本介紹
- 中文名：無義介導的mRNA降解
- 外文名：nonsense-mediated mRNA decay
Nonsense-mediated mRNA decay(NMD) is a RNA surveillance mechanism that detects the mRNAs harboring premature termination condons(PTC),and triggers the degradation to prevent the accumulation of truncated and potentially harmful proteins. NMD also regulates a subset of wild-type physiological transcripts, indicating that NMD plays an important biological role in eukaryotic cells. The key of NMD pathway is PTC recognition from authentic stop condons during translation. Here we reviewed three models to elucidate different mechanisms found in mammals and invertebrates. The NMD effectors such as UPF1（up-frameshift） are involved in the “functional complex” assembly on PTC containing mRNA, although the details of sequential events remain to be clarified for the variety among different organisms, we present the latest progress in postPTC recognition events to better understand the molecular mechanism of NMD pathway.
