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Q/R RNA editing of the AMPA receptor subunit 2 (GRIA2) transcript evolves no later than the appearance of cartilaginous fishes
Author(s) -
Kung Shieh-Shiuh,
Chen Yu-Chia,
Lin Wei-Hsiang,
Chen Chun-Chen,
Chow Wei-Yuan
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)03183-0
Subject(s) - biology , intron , gene , rna editing , exon , genetics , coding region , vertebrate , rna
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.