Q/R RNA editing of the AMPA receptor subunit 2 (GRIA2) transcript evolves no later than the appearance of cartilaginous fishes
Q/R RNA editing of the AMPA receptor subunit 2 (GRIA2) transcript evolves no later than the appearance of cartilaginous fishes
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DOI：
10.1016/s0014-5793(01)03183-0
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发表时间：
2001-12-07
期刊：
影响因子：
3.5
通讯作者：
Chow, WY
中科院分区：
文献类型：
--
作者：
Kung, SS;Chen, YC;Chow, WY
脊椎动物AMPA受体亚基的孔衬片段（M2）的Q/R位点上的氨基酸（谷氨酰胺（Q）或精氨酸（R））严重影响受体的性质。哺乳动物AMPA受体亚基2（GRIA 2）转录物的R密码子不是由染色体序列编码的，而是由转录后RNA编辑活动产生的。另一方面，一些硬骨鱼GRIA 2同源物的R密码子由染色体序列编码。为了阐明Q/R RNA编辑在脊椎动物GRIA 2转录本修饰中的应用，对5种鱼类和1种两栖动物的GRIA 2基因进行了研究。假定的盲鳗GRIA 2同源物（hfGRIA 2）编码R密码子，而鲨鱼和牛蛙GRIA 2基因在基因组Q/R位点指定Q密码子。所有颚口线虫GRIA 2基因都具有一个内含子，将M2的编码区和第三疏水区（M3）分开。Q/R RNA编辑所需的内含子组分在所有Q编码脊椎动物GRIA 2基因中保留，但在R编码GRIA 2基因中不存在。有趣的是，hfGRIA 2是无内含子的，这表明hfGRIA 2不太可能从Q/R编辑能力基因进化而来。这项研究的结果表明，通过Q/R编辑修饰GRIA 2转录物最有可能是在无颌和颚口分离后获得的。(C)2001年欧洲生物化学学会联合会。由Elsevier Science B. V.出版，版权所有。
The amino acid, either a glutamine (Q) or an arginine (R), at the Q/R site of the pore-lining segment (M2) of a vertebrate AMPA receptor subunit critically influences the properties of the receptor. The R codon of the mammalian AMPA receptor subunit 2 (GRIA2) transcript is not coded by the chromosomal sequence, but is created by posttranscriptional RNA editing activities. On the other hand, the R codons of some teleost GRIA2 homologs are coded by chromosomal sequences. To elucidate the evolution of the utilization of Q/R RNA editing in modifying vertebrate GRIA2 transcripts, the GRIA2 genes of five fish species and an amphibian were studied. The putative hagfish GRIA2 homolog (hfGRIA2) encodes an R codon, whereas shark and bullfrog GRIA2 genes specify a Q codon at the genomic Q/R site. All gnathostoma GRIA2 genes possess an intron splitting the coding regions of M2 and the third hydrophobic region (M3). The intronic components required for Q/R RNA editing are preserved in all the Q-coding vertebrate GRIA2 genes but are absent from the R-coding GRIA2 genes. Interestingly, the hfGRIA2 is intronless, suggesting that hfGRIA2 is unlikely evolved from a Q/R editing-competent gene. Results of this study suggest that modification of GRIA2 transcripts by Q/R editing is most likely acquired after the separation of the Agnatha and Gnathostome. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.