Identification and characterization of single-nucleotide polymorphisms in MCH-R1 and MCH-R2.
OBJECTIVE
To identify and functionally characterize single-nucleotide polymorphisms (SNPs) in melanin-concentrating hormone (MCH)-R1 and -R2.


METHODS
The entire coding regions and intron/exon splice junction regions of MCH-R1 and MCH-R2 were sequenced from anonymous white (n=45) and African-American (n=46) individuals. DNA was analyzed, and SNPs were identified using Phred, Phrap, and Consed software. DNA constructs containing MCH-R1 and MCH-R2 SNPs were generated and expressed in CHO cells. The effect of the SNPs in MCH-R1 and MCH-R2 were assessed in receptor binding assays and functional assays measuring changes in intracellular cAMP and Ca2+ levels.


RESULTS
We identified 12 SNPs in the MCH-R1 gene. Two of these SNPs are in coding regions, and one produces an arginine-for-glycine substitution at residue 34 in the MCH-R1 sequence. This SNP is present at a minor allele frequency of 15% in the African-American population tested in this study. We identified eight SNPs in the MCH-R2 gene. Four of these SNPs are in coding regions, and two produce amino acid substitutions. Lysine substitutes for arginine at residue 63 of the African-American population, and glutamine substitutes for arginine at residue 152 in whites (minor allele frequency of 2% for both SNPs). No changes in receptor binding or functional signaling were observed with the SNP mutations in MCH-R1 or MCH-R2.


CONCLUSIONS
These data indicate that potential therapeutics designed to act at the MCH receptor are unlikely to have altered effects in subpopulations that express variant forms of MCH-R1 or MCH-R2.
Hawes
Brian E
BE
K15-3600, Schering Plough Research Institute, 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA. brian.hawes@spcorp.com
Green
Beverly
B
O'Neill
Kim
K
Fried
Steve
S
Arreaza
M Gladys
MG
Qiu
Ping
P
Simon
Jason S
JS
D000595:Amino Acid Sequence; D044383:Black People; D005091:Exons; D006801:Humans; D007028:Hypothalamic Hormones / Q000737:chemistry / Q000378:metabolism; D007438:Introns; D008543:Melanins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010907:Pituitary Hormones / Q000737:chemistry / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic / Q000235:genetics; D012326:RNA Splicing; D043562:Receptors, G-Protein-Coupled; D011979:Receptors, Pituitary Hormone / Q000235:genetics*; D017481:Receptors, Somatostatin / Q000235:genetics*; D017422:Sequence Analysis, DNA; D044465:White People; D001741:Black or African American
D007028:Hypothalamic Hormones; C103263:MCHR1 protein, human; C431280:MCHR2 protein, human; D008543:Melanins; D010907:Pituitary Hormones; D043562:Receptors, G-Protein-Coupled; D011979:Receptors, Pituitary Hormone; D017481:Receptors, Somatostatin; C019463:melanin-concentrating hormone