[Cloning and functional analysis of melanocortin 4 receptor mutation gene F261S].
OBJECTIVE
To evaluate the function change of the melanocortin 4 receptor (MC4R) protein with mutation of F261S.


METHODS
Human embryonic cells of the HEK293 line were cultured. Wild-type genomic DNA and F261S mutation human melanocortin 4 receptor genes from the genomic DNA of aproband of homozygotic F612 mutation were amplified and cloned into a topo-TA eukaryotic expression plasmid vector. After the wild-type and F261S mutated proteins were expressed in HEK293 cells, alpha-MSH (10(-11) approximately 10(-5) mmol/L) was added, then the intracellular cAMP was detected with dual luciferase reporter assay system.


RESULTS
When the concentration of alpha-MSH added was 10(-9) approximately 10(-8) mmol/L, the intracellular alpha-MSH concentration of the cells transfected with wild-type MC4R gene was significantly higher than that of the cells transfected with F261S mutation gene (P < 0.05). When the concentration of alpha-MSH added went to 10(-7) approximately 10(-5) mmol/L, the differences became even more significant (all P < 0.01).


CONCLUSIONS
The novel MC4R mutation F261S undermines the signal transduction. It may be the possible reason leading to monogenic mutation obesity in Chinese.
Shao
Xin-Yu
XY
Shanghai Diabetes Institute, Shanghai Jiaotong University Affiliated Sixth Hospital, Shanghai 200233, China.
Jia
Wei-Ping
WP
Cai
Shu-Bing
SB
Fang
Qi-Chen
QC
Zhang
Rong
R
Lu
Jun-Xi
JX
Xiang
Kun-San
KS
D000328:Adult; D000368:Aged; D002648:Child; D002681:China; D003001:Cloning, Molecular; D005260:Female; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D009765:Obesity / Q000235:genetics*; D010375:Pedigree; D044105:Receptor, Melanocortin, Type 4 / Q000235:genetics* / Q000378:metabolism / Q000502:physiology
C470072:MC4R protein, human; D044105:Receptor, Melanocortin, Type 4