Point mutation in an AMPA receptor gene rescues lethality in mice deficient in the RNA-editing enzyme ADAR2
Point mutation in an AMPA receptor gene rescues lethality in mice deficient in the RNA-editing enzyme ADAR2
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DOI：
10.1038/35017558
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发表时间：
2000-07-06
期刊：
影响因子：
64.8
通讯作者：
Seeburg, PH
中科院分区：
文献类型：
--
作者：
Higuchi, M;Stefan, M;Seeburg, PH
通过腺苷位点选择性脱氨为肌苷（1，2）的RNA编辑改变了核转录物（6）中的密码子（3，4）和剪接（5），从而改变了蛋白质功能。ADAR 2（参考文献7，8）是一种在脑和其他组织中广泛表达的候选哺乳动物编辑酶（7），但其RNA底物未知。在这里，我们研究了ADAR 2介导的RNA编辑，通过产生针对靶向功能无效等位基因纯合的小鼠。ADAR 2（-/-）小鼠中的编辑在多种转录物中的25个位置中的大多数位置处大幅减少（3-6）;突变小鼠变得易于癫痫发作并过早死亡。受损的表型似乎完全由单个编辑不足的位置引起，因为当编辑不足的转录物的两个等位基因被编码编辑版本的等位基因外显子取代时，它恢复正常（9）。关键位置指定了AMPA（α-氨基-3-羟基-5-甲基-4-异恶唑丙酸酯）受体（10）GluR-B前信使RNA中的离子通道决定簇（10），即Q/R位点（3，6）。我们的结论是，这种转录是生理上最重要的底物ADAR 2。
RNA editing by site-selective deamination of adenosine to inosine(1,2) alters codons(3,4) and splicing(5) in nuclear transcripts(6), and therefore protein function. ADAR2 (refs 7, 8) is a candidate mammalian editing enzyme that is widely expressed in brain and other tissues(7), but its RNA substrates are unknown. Here we have studied ADAR2-mediated RNA editing by generating mice that are homozygous for a targeted functional null allele. Editing in ADAR2(-/-) mice was substantially reduced at most of 25 positions in diverse transcripts(3-6); the mutant mice became prone to seizures and died young. The impaired phenotype appeared to result entirely from a single underedited position, as it reverted to normal when both alleles for the underedited transcript were substituted with alleles encoding the edited version exonically(9). The critical position specifies an ion channel determinant(10), the Q/R site(3,6), in AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate) receptor(10) GluR-B pre-messenger RNA. We conclude that this transcript is the physiologically most important substrate of ADAR2.