• Biomolecules & Therapeutics
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• v.4 no.1
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• pp.103-109
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• 1996

To investigate the effect of the third intracellular loop (i3 loop) peptide of human $\beta$$_2$-adrenergic receptor on receptor agonist binding, we expressed third intracellular loop region of human $\beta$$_2$-adrenergic receptor as glutathione S-transferase fusion protein in E. coli. DNA fragment of the receptor gene which encodes amino acid 221-274 of human $\beta$$_2$-adrenergic receptor was amplified by polymerase chain reaction and subcloned into the bacterial fusion protein expression vector pGEX-CS and expressed as a form of glutathione-S-transferase (GST) fusion protein in E. coli DH5$\alpha$. The receptor fusion protein was identified by SDS-PAGE and Western blot using monoclonal anti-GST antibody. The fusion protein expressed in this study was purified to an apparent homogeneity by glutathione Sepharose CL-4B affinity chromatography. The purified i3 loop fusion proteins at a concentration of 10 $\mu\textrm{g}$/ι caused right shift of the isoproterenol competition curve of [$^3$H]Dihydroalprenolol binding to hamster lung $\beta$$_2$-adrenergic receptor indicating lowered affinity of isoproterenol to $\beta$$_2$-adrenergic receptor possibly due to the uncoupling of receptor and G protein in the presence of the fusion protein. The uncoupling of receptor and G protein suggests that i3 loop region plays a critical role on $\beta$$_2$-adrenergic receptor G protein coupling.

• BMB Reports
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• v.55 no.10
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• pp.500-505
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• 2022

Uncoupling protein 2 (Ucp2) was first introduced as a member of Uncoupling protein family and a regulator of ROS formation; however, its role in adipose tissue is not fully understood. In the present study, we have investigated the role of Ucp2 against high-fat diet (HFD)-induced obesity in epididymal white adipose tissue (eWAT) and browning of inguinal white adipose tissue (iWAT). Diet-induced obesity is closely related to macrophage infiltration and the secretion of pro-inflammatory cytokines. Macrophages surround adipocytes and form a crown-like-structure (CLS). Some reports have suggested that CLS formation requires adipocyte apoptosis. After 12 weeks of HFD challenge, Ucp2 knockout (KO) mice maintained relatively lean phenotypes compared to wild-type (WT) mice. In eWAT, macrophage infiltration, CLS formation, and inflammatory cytokines were reduced in HFD KO mice compared to HFD WT mice. Surprisingly, we found that apoptotic signals were also reduced in the Ucp2 KO mice. Our study suggests that Ucp2 deficiency may prevent diet-induced obesity by regulating adipocyte apoptosis. However, Ucp2 deficiency did not affect the browning capacity of iWAT.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1065-1070
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• 2006

The avian uncoupling protein (avUCP) is a member of the mitochondrial transporter superfamily that uncouples proton entry in the mitochondrial matrix from ATP synthesis. The sequencing analysis method was used to identify nucleotide polymorphisms within the avUCP gene in Korean native chicken (KNC). This study identified ten single nucleotide polymorphisms (SNPs) in the avUCP gene. We analyzed the SNPs of the avUCP gene to investigate whether polymorphism in the gene might be responsible for quantitative variations in economic traits in KNC. Three significant polymorphic sites for economic traits were avUCP C+282T (mean body weight, p<0.05), avUCP C+433T (daily percent lay, p<0.05), and avUCP T+1316C (daily percent lay, p<0.05). The frequency of each SNP was 0.125 (C+282T in avUCP gene exon 1 region), 0.150 (C+433T in avUCP gene intron 1 region), and 0.15 (T+1316C in avUCP gene exon 3 region), respectively. Among the identified SNPs, one pair of SNPs (genotype CC, C+282T and TT, avUCP C+433T) showed the highest daily percent lay (p<0.05) and mean body weight (p<0.05) and the frequency was 0.067. This study of the avUCP gene could be useful for genetic studies of this gene and selection on economic traits for KNC.

• Preventive Nutrition and Food Science
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• v.10 no.3
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• pp.279-284
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• 2005

Uncoupling protein-1 (UCP-1) plays a major role in thermogenesis, and has been implicated in the pathogenesis of obesity and metabolic disorders. The aim of this study was to estimate the effects of A-3826G polymorphism of UCP-1 gene on body fat distribution. Two hundred forty eight Korean female overweight subjects with BMI more than 25 kgfm2 participated in this study. The areas of abdominal subcutaneous and visceral fat of all subjects were measured from computed tomography cross sectional pictures of the umbilical region. Subcutaneous fat areas of upper and lower thigh were also measured. Body composition was measured by bio-impedance analysis, and serum concentrations of biochemical parameters, such as glucose, triglyceride, cholesterol etc, were also measured. Genotype of UCP-1 was analyzed by polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method. The frequencies of UCP-1 genotypes were AA type; $27.8\%,\;AG\;type;\;51.2\%\;and\;GG\;type;\;21.0\%,$ and the frequency of G allele was 0.47. Body weight, BMI, WHR, SBP, DBP and body compositions were not significantly different by UCP-1 genotype. Abdominal visceral fat area was significantly higher in AG and GG type compared with AA type (p=0.009), but subcutaneous fat areas were not significantly different by UCP-1 genotype. Among biochemical parameters, LDL cholesterol level was significantly higher in GG type compared with AA and AG types (p=0.033). Among all subjects, 121 subjects finished 1 month weight loss program containing hypocaloric diet and exercise. The reduction of body weight and BMI were lower in GG type compared with AA/AG type even though statistical significances were not found (p > 0.05). These results suggest that UCP-1 genotype has a significant effect on visceral fat accumulation among Korean female overweight subjects with BMI more than $25\;kg/m^2$.

• Environmental Mutagens and Carcinogens
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• v.22 no.1
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• pp.39-46
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• 2002

Obesity is a complex metabolic disorder with a strong genetic component. There are many candidate genes for obesity and its related phenotypes. We studied genetic variations between Korean obese and lean groups. Polymorphisms investigated were the Msp I polymorphism of the $\alpha$$_{2A}$-adrenergic receptor ($\alpha$$_{2A}$-AR) gene, the Mnl I polymorphism of the $\alpha$$_2$-adrenergic receptor ($\alpha$$_2$-AR) gene, the BstO I polymorphism of the $\beta$$_3$-adrenergic receptor ($\beta$$_3$-AR) gene, the Pml I polymorphism of the lamin A/C (LMNA) gene, the Hga I polymorphism of the clearance receptor (NPRC) gene, the Msp I polymorphism of the leptin gene, BclI polymorphism of the uncoupling protein 1 (UCPI) gene and the Hha I polymorphism of the fatty acid binding protein 2 (FABP2) gene. Among these genetic markers, Pml I polymorphism at the LMNA gene and Bcl I polymorphism at the UCP1 gene were significantly associated with obesity. However, further studies are required whether thease findings are reproduced in large population, although two polymorphisms might be useful as genetic markers in the ethiology of obesity in Korean population.ion.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.186-189
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• 2023

Uncoupling protein 1 (UCP1) is a unique mitochondrial membranous protein expressed in brown adipose tissue (BAT) in mammals. While its expression in response to cold temperatures and adipogenic inducers is well-characterized in mammals and human infants, the molecular characterization and expression of UCP1 in fish remain unexplored. To address this gap, we analyzed UCP1 expression in response to adipogenic inducers in a fish cell line, rainbow trout gonadal cells (RTG-2), and compared it with UCP1 expression in three mammalian preadipocytes, 3T3-L1, T37i, and WT1 exposed to the Peroxisome proliferator-activated receptor gamma (PPARγ) agonists, rosiglitazone (Rosi). In mammalian preadipocytes, UCP1 protein was highly expressed by Rosi, with an induction of adipogenesis observed in a time-dependent manner. This suggests that UCP1 plays a significant role in adipogenesis in mammals. However, RTG-2 cells showed no response to adipogenic inducers and exhibited only marginal expressions of UCP1. These results imply that RTG-2 cells may lack crucial responsive mechanisms to adipogenic signals or that the adipogenic response is regulated by other mechanisms. Further studies are needed to confirm these phenomena in fish preadipocytes when an appropriate cell line is established in future research.

• Journal of Animal Science and Technology
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• v.58 no.1
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• pp.3.1-3.6
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• 2016

Background: Uncoupling proteins 2 (UCP2) plays an important role in energy regulation, previous studies suggested that UCP2 is an excellent candidate gene for human obesity and growth-related traits in cattle and chicks. The current study was designed to detect the genetic variation of UCP2 gene, and to explore the association between polymorphism of UCP2 gene and growth, carcass and meat quality traits in rabbits. Results: A synonymous mutation in exon 1 and four variants in the first intron of the UCP2 gene were identified by using PCR-sequencing. The synonymous mutation c.72G>A was subsequently genotyped by MassArray system (Sequenom iPLEXassay) in 248 samples from three meat rabbit breeds (94 Ira rabbits, 83 Champagne rabbits, and 71 Tianfu black rabbits). Association analysis suggested that the individuals with AA and AG genotypes showed greater 70 d body weight (P < 0.05), 84 d body weight (P < 0.01), ADG from 28 to 84 days of age (P < 0.05), eviscerated weight (P < 0.01), semi-eviscerated weight (P < 0.01) and semi-eviscerated slaughter percentage (P < 0.05), respectively. Additionally, the individuals with AA and AG genotype had a lower pH value of longissimus muscle (P < 0.01) and hind leg muscle (P < 0.05) after slaughter 24 h. Conclusions: These findings indicated that UCP2 could be a candidate gene that associated with growth performance, body composition and meat quality in rabbits, and this would contribute to advancements in meat rabbit breeding practice.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.823-830
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• 2005

This study was undertaken to evaluate the effect of bacteria-derived $\beta$-glucan fiber on serum lipids, adiposity and uncoupling protein (UCP) expression in rats. In order to induce obesity, Sprague-Dawley weanling male rats were allowed free access to AIN-76A diet until 4 weeks of age, and fed high-fat diet (beef tallow, $40\%$ of calories as fat) for 6 weeks until 10 weeks of age. Rats were then fed with $0\%$ thigh- fat control group), $1\%$, or $5\%$ bacterial ~-glucan supplemented high-fat diets (w/w) for another 6 weeks. For comparison, normal control group was fed with AIN-76 diet $11.7\%$ fat). Supplementation with bacterial $\beta$-glucan resulted in a significant reduction of high-fat-induced white fat (i.e., visceral and peritoneal fat) development, adipocyte hypertrophy, and development of hyperinsulinemia and hyperleptinemia. Serum triglyceride, total cholesterol, and free fatty acid levels were greatly reduced, but, HDL-cholesterol concentrations were increased by bacterial $\beta$-glucan supplementation. Serum leptin level was lower in the $\beta$-glucan groups than in the high-fat group. The expression of UCPs (UCP1, UCP2, and UCP3) in brown adipose tissue (BAT) were significantly increased by $5\%$ bacterial $\beta$-glucan-containing diet. This study suggests that the anti-obesity effect of $5\%$ bacterial $\beta$-glucan is attributed to upregulation of UCPs and inefficient energy utilization.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.796-804
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• 2004

We found previously that dietary high fat caused obesity, and levan supplementation to the regular diet reduced adiposity and serum lipids. In the present study, we examined the effects of levan [high-molecular-mass $\beta$-(2,6)-linked fructose polymer] supplement on the development of obesity and lipid metabolism in rats fed with high-fat diet. Thus, to determine whether the dietary levan may have the anti-obesity and hypolipidemic effects, 4-wk-old Sprague Dawley male rats were fed with high-fat diet for 6 wk to induce obesity, and subsequently fed with 0, 1, 5, or 10% levan supplemented high-fat diets (w/w) for another 4 wk. For the comparison, a normal control group was fed with AIN-76A diet. Supplementation with levan resulted in a significant reduction of high-fat-induced body weight gain, white fat (i.e., epididymal, visceral, and peritoneal fat) development, adipocyte hypertrophy, and the development of hyperinsulinemia and hyperlipidemia in a dose-dependent manner. Serum triglyceride and free fatty acid levels were greatly reduced by levan supplementation. Serum total cholesterol level was reduced, whereas the HDL cholesterol level was increased by dietary levan. The expression of uncoupling protein (UCP) was increased by dietary high fat, and was further induced by levan supplementation. The mRNA level of UCP1, 2, and 3 in brown adipose tissue (BAT) and UCP3 in skeletal muscle was upregulated in rats fed with dietary levan. In conclusion, upregulated UCP mRNA expression may contribute to suppression of development of obesity through increased energy expenditure. The present results suggest that levan supplementation to the diet is beneficial in suppressing diet-induced obesity and hyperlipidemia.