BRIEF REPORTS 425 11. Monaghan, D. T., Bridges, R. J., and Cotman, C. W. (1989). units of Taq DNA polymerase, and 0.25 units of Pfu DNA The excitatory amino acid receptors: Their classes, pharma- polymerase. The PCR conditions were initial denaturation cology, and distinct properties in the function of the central for 2 min at 94°C followed by 30 cycles consisting of 1.5 nervous system. Annu. Rev. Pharmacol. Toxicol. 29: 365– min at 94°C, annealing for 2 min at 60°C, and extension 402. for 8 min at 72°C; the final extension was 10 min at 72°C. 12. Monyer, H., Burnashev, N., Laurie, D. J., Sakmann, B., and A 5.6-kb fragment was obtained after amplification. We Seeburg, P. H. (1994). Developmental and regional expression partially sequenced it and determined the exon/intron in the rat brain and functional properties of four NMDA recep- structure of UCP3 between the start and the stop codons. tors. Neuron 12: 529–540. The positions and sizes of the introns are shown in Fig. 13. Nakanishi, S. (1992). Molecular diversity of glutamate recep- 1. The five introns interrupt the UCP3 cDNA sequence tors and implications for brain function. Science 258: 597– (GenBank Accession No. U84763) after nucleotides 279, 603. 490, 694, 796, and 977 to divide the coding region into six 14. Takano, H., Onodera, O., Hajime, T., Mori, H., Sakumura, K., exons. It is noteworthy that the partial genomic structure Hori, T., Kobayashi, H., Mishino, M., and Tsuji, H. (1993). Chro- of the UCP3 gene shows a high similarity to that of UCP1, mosomal localization of the e1, e3 and z1 subunit genes of the which was found also to consist of six exons, each of which human NMDA receptor channel. Biochem. Biophys. Res. Com- mun. 197(2): 922–926. encodes a putative transmembrane a-helix (2, 6). To establish the chromosomal location of UCP3, we used two oligonucleotide primers designed in the fifth intron: forward primer 5-TTCGAATGTGGCTACCGTGG-3  and reverse primer 5 -CAGCTCTTGTTCACTTGTTGG-3 . They were found to amplify, from the human genome, a product of ca. 900 bp, which was checked by sequencing. Genomic Structure of Uncoupling These primers were first used to map UCP3 with a panel Protein-3 (UCP3) and Its Assignment of monochromosomal somatic cell hybrids containing sin- gle human chromosomes (provided by the Human Genome to Chromosome 11q13 Mapping Project Resource Center, Medical Research Council, UK) (3). The PCR conditions were initial denatur- Olivier Boss, 1 Jean-Paul Giacobino, ation for 2 min at 94°C followed by 30 cycles consisting of and Patrick Muzzin 1.5 min at 94°C, annealing for 1.5 min at 58°C, and exten- Department of Medical Biochemistry, Faculty of Medicine, University sion for 1.5 min at 72°C; the final extension was 10 min at of Geneva, 1 Michel Servet, 1211 Geneva 4, Switzerland 72°C. The PCR products were visualized with ethidium bromide staining following fractionation on a 1.5% agarose Received August 18, 1997; accepted November 10, 1997 gel by electrophoresis. They were also blotted and identi- fied by Southern blot analysis with a human UCP3 DNA probe. A strong signal of the expected size was detected in the Mitochondrial uncoupling protein-1 (UCP1) is a highly monochromosomal cell containing human chromosome 11, tissue-specific proton carrier that induces heat production and a weaker but reproducible signal was detected in the in brown adipose tissue (BAT) by uncoupling respiration cell containing human chromosome 15 (not shown). This from ATP synthesis (7). Very recently, novel UCPs have faint signal might be due to contamination of the chromo- been cloned: UCP2, which is ubiquitously expressed in hu- some 15 cell hybrids by chromosome 11. mans (4), and UCP3, which is specifically expressed in skel- Chromosomal mapping was then performed with the Gene- etal muscle in humans and is the predominant UCP in this Bridge 4 Radiation Hybrid DNA panel (provided by the Hu- tissue (1). man Genome Mapping Project Resource Center, Medical Re- UCP1 has been found to be located on human chromo- search Council, UK) (8). PCR amplification was performed some 4q31 (2) and UCP2 on human chromosome 11q13 as described above with the same primers, and the results of between markers D11S916 and D11S911 (4). The chromo- PCR screening were submitted to the Whitehead Institute, somal location of UCP3 is unknown. MIT, Center for Genome Research (http://www-genome.wi. We first studied the genomic structure of human UCP3. mit.edu/cgi-bin/contig/rhmapper.pl) to find the UCP3 For this purpose we amplified the UCP3 gene from human gene position on the Radiation Hybrid framework map. genomic DNA with oligonucleotide primers extending over This mapping placed UCP3 in the D11S916–D11S3966 the start and stop codons: UCP3START 5-CAGGACTAT- (WI-6189) interval within 11q13. UCP2, an uncoupling GGTTGGACTGAAGCCTTC-3  and UCP3STOP 5-TGG- protein-1 homologue that is 73% identical to UCP3, has CCTTCTTGTCTTGTTCAAAACG-3 . PCR was performed been found to be located on chromosome 11q13 between in a 50-ml reaction mixture containing 10 ng of human genomic DNA in 20 mM Tris–HCl (pH 8.4), 50 mM KCl, D11S916 and D11S911 (4). Thus, radiation hybrid map- 2 mM MgCl 2 , 0.4 mM each primer, 200 mM each dNTP, 2.5 ping assigns these related genes to a similar location on chromosome 11. Linkage studies have revealed the existence of a suscep- 1 To whom correspondence should be addressed. Telephone: tibility locus for insulin-dependent diabetes mellitus (/4122) 702 54 87. Fax: (/4122) 702 55 02. E-mail: Olivier.Boss@ medecine.unige.ch. (IDDM) in the region of the FGF3 gene on chromosome GENOMICS 47, 425–426 (1998) ARTICLE NO. GE975135 0888-7543/98 $25.00 Copyright  1998 by Academic Press All rights of reproduction in any form reserved.