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Cloning, Functional Coexpression, and Pharmacological Characterisation of Human cDNAs Encoding NMDA Receptor NR1 and NR2A Subunits
Author(s) -
Bourdellès B.,
Wafford K. A.,
Kemp J. A.,
Marshall G.,
Bain C.,
Wilcox A. S.,
Sikela J. M.,
Whiting P. J.
Publication year - 1994
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1994.62062091.x
Subject(s) - biology , microbiology and biotechnology , complementary dna , gamma aminobutyric acid receptor subunit alpha 1 , protein subunit , interleukin 10 receptor, alpha subunit , gene isoform , alternative splicing , molecular cloning , amino acid , ifenprodil , recombinant dna , peptide sequence , interleukin 5 receptor alpha subunit , biochemistry , nmda receptor , receptor , gene , g alpha subunit
Using expression cloning, and more recently using polymerase chain reaction cloning approaches, a family of rat N ‐methyl‐ d ‐aspartate (NMDA) receptor subunit cDNAs has been described (NR1, NR2A, NR2B, NR2C, and NR2D). Here we report cloning and sequencing of cDNAs encoding isoforms of the human NR1 subunit (NR1a, NR1d, and NR1e) that differ at their C‐terminal end as a result of alternative splicing and also of a cDNA encoding the human NR2A subunit. The deduced amino acid sequences of the human NR1 subunit isoforms differed from the published rat NR1 subunit sequences at only eight positions, all of which were N‐terminal to the alternatively spliced domains. The human NR2A subunit deduced amino acid sequence differed from the published rat NR2A subunit sequence at 81 of the 1,464 amino acids, with most of the substitutions being located in the C‐terminal half of the subunit. The gene for NR2A has been localised to human chromosome 16. We also report the expression and pharmacological characterisation of recombinant human NR1a/NR2A heteromeric receptors in Xenopus oocytes. These receptors had EC 50 values of 2.14 and 2.05 μ M for glutamate and glycine, respectively, and an IC 50 of 46.8 μ M for Mg 2+ . Responses were antagonised by d ‐2‐amino‐5‐phosphonovalerate, L‐689,560, pH 6.3, zinc, and MK‐801. No modulatory effect was observed on application of ifenprodil, confirming previous observations with rat NR1 + NR2A recombinant receptors.