A novel missense mutation in the mouse growth hormone gene causes semidominant dwarfism, hyperghrelinemia, and obesity.
The SMA1-mouse is a novel ethyl-nitroso-urea (ENU)-induced mouse mutant that carries an a-->g missense mutation in exon 5 of the GH gene, which translates to a D167G amino acid exchange in the mature protein. Mice carrying the mutation are characterized by dwarfism, predominantly due to the reduction (sma1/+) or absence (sma1/sma1) of the GH-mediated peripubertal growth spurt, with sma1/+ mice displaying a less pronounced phenotype. All genotypes are viable and fertile, and the mode of inheritance is in accordance with a semidominant Mendelian trait. Adult SMA1 mice accumulate excessive amounts of sc and visceral fat in the presence of elevated plasma ghrelin levels, possibly reflecting altered energy partitioning. Our results suggest impaired storage and/or secretion of pituitary GH in mutants, resulting in reduced pituitary GH and reduced GH-stimulated IGF-1 expression. Generation and identification of the SMA1 mouse exemplifies the power of the combination of random mouse mutagenesis with a highly detailed phenotype-analysis as a successful strategy for the detection and analysis of novel gene-function relationships.
Meyer
Carola W E
CW
Department of Biology and Animal Physiology, Karl-von-Frisch Strasse, Philipps University Marburg, D-35043 Marburg, Germany. meyerc@staff.uni-marburg.de
Korthaus
Dirk
D
Jagla
Wolfgang
W
Cornali
Emmanuelle
E
Grosse
Johannes
J
Fuchs
Helmut
H
Klingenspor
Martin
M
Roemheld
Stephanie
S
Tschöp
Matthias
M
Heldmaier
Gerhard
G
De Angelis
Martin Hrabé
MH
Nehls
Michael
M
D000273:Adipose Tissue; D000595:Amino Acid Sequence; D000818:Animals; D001823:Body Composition / Q000235:genetics; D001835:Body Weight / Q000235:genetics; D004392:Dwarfism / Q000235:genetics*; D005091:Exons; D005260:Female; D005298:Fertility; D008040:Genetic Linkage; D005838:Genotype; D054439:Ghrelin; D013006:Growth Hormone / Q000032:analysis / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D009765:Obesity / Q000235:genetics*; D036361:Peptide Hormones / Q000097:blood*; D010641:Phenotype; D010902:Pituitary Gland / Q000737:chemistry; D016415:Sequence Alignment
D054439:Ghrelin; D036361:Peptide Hormones; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone