Molecular cloning, chromosomal mapping, and functional expression of human brain glutamate receptors.
A full-length cDNA clone encoding a glutamate receptor was isolated from a human brain cDNA library, and the gene product was characterized after expression in Xenopus oocytes. Degenerate PCR primers to conserved regions of published rat brain glutamate receptor sequences amplified a 1-kilobase fragment from a human brain cDNA library. This fragment was used as a probe for subsequent hybridization screening. Two clones were isolated that, based on sequence information, code for different receptors: a 3-kilobase clone, HBGR1, contains a full-length glutamate receptor cDNA highly homologous to the rat brain clone GluR1, and a second clone, HBGR2, contains approximately two-thirds of the coding region of a receptor homologous to rat brain clone GluR2. Southern and PCR analysis of a somatic cell-hybrid panel mapped HBGR1 to human chromosome 5q31.3-33.3 and mapped HBGR2 to chromosome 4q25-34.3. Xenopus oocytes injected with in vitro-synthesized HBGR1 cRNA expressed currents activated by glutamate receptor agonists with the following specificity sequence: domoate greater than kainate much greater than quisqualate greater than or equal to alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid greater than or equal to L-glutamate much greater than N-methyl-D-aspartate. The kainate-elicited currents were specifically blocked by 6-cyano-7-nitroquinoxaline-2,3-dione but were insensitive to 2-amino-5-phosphonovalerate and kynurenic acid. These results indicate that clone HBGR1 codes for a glutamate receptor of the kainate subtype cognate to members of the glutamate receptor family from rodent brain.
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Department of Biology, University of California, San Diego, La Jolla 92093.
Ferrer-Montiel
A V
AV
Schinder
A F
AF
McPherson
J P
JP
Evans
G A
GA
Montal
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002874:Chromosome Mapping; D002894:Chromosomes, Human, Pair 4; D002895:Chromosomes, Human, Pair 5; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D007608:Kainic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000235:genetics*; D014982:Xenopus laevis
D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D004247:DNA; C012301:domoic acid; D007608:Kainic Acid