Dissection of mRNA degradation pathways and anomalies associated with targeted disruption of CCR4-NOT deadenylase complex

我们通过生成编码CCR4-NOT复合物单个亚基的基因被破坏的小鼠品系，研究了CCR4-NOT deadenylase复合物的生理作用。我们对由此产生的小鼠进行了病理和解剖分析，迄今为止，我们发现这些小鼠要么是胚胎致死，要么是组织发育异常，要么是免疫系统和/或能量代谢的调节丧失。因此，我们假设CCR4-NOT缺陷小鼠系可能是人类疾病的模型。我们还分析了CCR4-NOT复合物识别和降解其靶mrna的聚(A)尾部的分子机制。我们解决了低聚（dA）相互作用的酶亚基CNOT6L和CNOT7的晶体结构。我们还发现酶亚基可以通过与调节亚基（如CNOT1和CNOT3）的相互作用来靶向特定mRNA物种的多(A)尾，这些亚基可以识别特定mRNA的3'UTR区域的特定序列。

We have studied the physiological roles of the CCR4-NOT deadenylase complex by generating mouse lines in which each gene encoding individual subunit of the CCR4-NOT complex is disrupted. Mice thus produced were analyzed pathologically and anatomically, and we so far found that those mice were either embryonic lethal or abnormal in tissue development or showed loss of regulation in immune system and/or energy metabolism. We, therefore, assumed that CCR4-NOT deficient mouse lines could be models of human diseases. We also analyzed the molecular mechanisms by which the CCR4-NOT complex recognizes and degrades poly(A) tail of its target mRNAs. We solved the crystal structures of oligo(dA)-interacting enzymatic subunits CNOT6L and CNOT7. We also found the enzymatic subunits can target poly(A) tail of specific mRNA species through their interaction with regulatory subunits such as CNOT1 and CNOT3 that can recognize specific sequences present at 3'UTR regions of particular mRNAs.