Isolation and characteristics of the melanocortin 1 receptor gene (MC1R) in the Chinese yakow (Bos grunniens×Bos taurus)

The Chinese yakow is the offspring of yak (Bos grunniens) and Yellow cattle (Bos taurus). The melanocortin 1receptor gene (MC1R) plays a crucial role in determining coat colour of mammals. To investigate the relationship of polymorphism of the MC1R with coat colour in the Chinese yakow, the coding sequence (CDS) and the flanking region of MC1R were sequenced from 84 Chinese yakow samples and compared with the sequences of the MC1R from other bovid species. A fragment of 1134 base pair (bp) sequences including the full CDS (954bp) and parts of the 5'- and 3'-untranslated regions (162 and 18bp, respectively) of the Chineseyakow MC1R were obtained. A total of 13 single nucleotide polymorphisms (SNPs) including 4 SNPs (T-129C, A-127C, C-106T, G-1A) in the 5'-untranslated region and 9 SNPs (C201T, T206C, C340A, C375T, T663C, G714C, C870T, G871A and T890C) in the CDS were identified, revealing high genetic variability. Four novel SNPs including T206C, G714C, C870T and T890C, which have not been reported previously in bovid species, were retrieved. Within 9 coding SNPs, C201T, C375T, T663C and C870T were silent mutations, while T206C, C340A, G714C, G871A and T890C were mis-sense mutations, corresponding to amino acid changes p.L69P, p.Q114K, p.K238N, p.A291N and p.I297T, respectively. Amino acid sequences alignment showed a more than 96% similarity with other ruminates. However, three classical bovine MC1R loci the E(D), E(+) and e were not retrieved in the Chinese yakow, indicating other genes or factors could be involved in affecting coat colour in this species.     

Genetic variability of the coding region for the prion protein gene (PRNP) in gayal (Bos frontalis)

The gayal (Bos frontalis) is a rare semi-wild bovid species in which bovine spongiform encephalopathy (BSE) has not been reported. Polymorphisms of the prion protein gene (PRNP) have been correlated significantly with resistance to BSE. In this study, the coding region of PRNP was cloned and characterized in samples from 125 gayal. A total of ten single nucleotide polymorphisms (SNPs), including six silent mutations (C60T, G75A, A108T, G126A, C357T and C678T) and four mis-sense mutations (C8A, G145A, G461A and C756G), corresponding to amino acids T3K, G49S9, N154S and I252M were identified, revealing high genetic diversity. Three novel SNPs including C60T, G145A and C756G, which have not been reported previously in bovid species, were retrieved. There also was one insertion–deletion (187Del24) at the N-terminal octapeptide repeat region. Alignment of nucleotide and amino acid sequences showed a high degree of similarity with other bovid species. Using phylogenetic analyses it was revealed that gayal has a close genetic relationship with Zebu cattle. In short, preliminary information is provided about genotypes of the PRNP in gayal. This could assist with the study of the pathogenesis of transmissible spongiform encephalopathies and cross species transmission as well as a molecular breeding project for gayal in China.     

Single nucleotide polymorphisms in the Melanocortin 1 Receptor gene are linked with lightness of fibre colour in Peruvian Alpaca (Vicugna pacos)

Melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor) (MC1R) is a gene‐controlling melanogenesis in mammals. However, it is not well characterized in alpacas and its association with colour is not known. The aim of this study was to look for polymorphisms in the MC1R gene in Peruvian Huacaya alpacas and to analyse the relationship between MC1R single nucleotide polymorphisms (SNPs) and the variations in the instrumental measurement of colour of alpaca fibre. Sixty alpaca fibre samples from black, brown, cream and white animals (15 for each colour) were used to extract DNA from hair bulbs. Colour was measured with a spectrophotometer to obtain quantitative values (CieL*a*b*). Sixteen samples, four of each colour group, were sequenced. Eighteen SNP mutations, 10 not previously described, were found in these 16 sequences. Three of them were chosen (c.82A>G, c.865C>T, c.901C>T) to analyse genotypes by PCR‐RFLP in the other 44 fibre samples and to determine the association of mutations with instrumental colour. These three polymorphisms showed association with fibre lightness (P < 0.05), although there was no correlation with colour groups.     

水牛、大额牛和牦牛抑制素α亚基编码基因外显子1多态性分析

为了揭示牛科物种INHA基因的遗传特征,该文采用PCR产物直接测序法对水牛、大额牛和牦牛INHA基因外显子1及其侧翼序列进行多态性检测,并结合已发表的包括牛科物种在内的一些哺乳动物数据进行了比较分析。结果表明,在水牛INHA基因外显子1中存在c.73C>A替换,为同义替换,河流型和沼泽型水牛编码产物一致;在大额牛的INHA基因外显子1中发现c.62C>T、c.187G>A替换,分别引起INHA中氨基酸发生p.P21L、p.V63M改变,两者均为相同性质氨基酸的替换;在牦牛中发现c.62C>T、c.129A>G替换,前者也引起编码氨基酸发生p.P21L替换,后者为同义替换。在INHA基因5’侧翼区所测出的序列中,水牛、大额牛和牦牛等物种内均未发现SNP位点,但在种间发现存在c.-6T>G的替换,大额牛、牦牛和普通牛均为c.-6G,而水牛为c.-6T。在INHA基因内含子中,水牛的第31～36位核苷酸处发现有6个碱基的缺失,即c.262+31₂62+36delTCTGAC;该位点在河流型水牛中野生型（+/+）占主体,而在沼泽型水牛中则缺失型（-/-）占主体。在大额牛、牦牛和普通牛等其它牛科物种的内含子中均未发现该缺失,但与水牛相比,大额牛、牦牛和普通牛内含子中发现缺失c.262+78₂62+79delTG。序列比对显示,INHA基因外显子1序列中c.43A和c.67G为水牛中所特有,而c.173A和c.255G为大额牛、牦牛和普通牛所共有,c.24C、c.47G、c.174T和c.206T为山羊所特有。大额牛、牦牛和普通牛间INHA基因外显子1序列差异较小,而山羊和水牛与它们间的差异相对较大。     

Polymorphism of THBS1 rs1478604 A>G in 5-untranslated region is associated with lymph node metastasis of gastric cancer in a Southeast Chinese population

Thrombospondin-1 plays an important role in cancer development and progression. This study investigated if a correlation exists between single-nucleotide polymorphisms (SNPs) in the Thrombospondin-1 gene (THBS1) and gastric cancer. We conducted a case-control study on a randomly recruited population of 283 patients and 283 healthy individuals from the city of Fuzhou in Southeast China. Individuals were genotyped for four SNPs (rs1478604 A>G, rs2228261 C>T, rs2292305 T>C, and rs3743125 C>T) in THBS1 using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. THBS1 genotypic distributions between the case and control groups were tested for correlations with cancer development. Comparisons between the case and control groups showed no significant differences in the genotypic distributions of rs1478604 A>G, rs2228261 C>T, and rs3743125 C>T. However, we found a statistically significant association between homozygous CC of THBS1 rs2292305 T>C and development of highly differentiated carcinoma (HDC). The rs1478604 A>G variant was found to be associated with invasion and lymph node metastasis in gastric cancer. After logistic regression and stratification analysis, rs1478604 A>G was more strongly associated with lymph node metastasis in HDC gastric cancer. The power to detect an effect for rs1478604 A>G in HDC was 90%. These findings indicate that the THBS1 rs1478604 A>G variant is linked with differential risks for gastric cancer nodal metastasis. These results support further investigation of THBS1 as a potential therapeutic target in gastric cancer.     

Coat colours in the Massese sheep breed are associated with mutations in the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes

Massese is an Italian dairy sheep breed characterized by animals with black skin and horns and black or apparent grey hairs. Owing to the presence of these two coat colour types, this breed can be considered an interesting model to evaluate the effects of coat colour gene polymorphisms on this phenotypic trait. Two main loci have been already shown to affect coat colour in sheep: Agouti and Extension coding for the agouti signalling protein (ASIP) and melanocortin 1 receptor (MC1R) genes, respectively. The Agouti locus is affected by a large duplication including the ASIP gene that may determine the Agouti white and tan allele (A(Wt)). Other disrupting or partially inactivating mutations have been identified in exon 2 (a deletion of 5 bp, D(5); and a deletion of 9 bp, D(9)) and in exon 4 (g.5172T>A, p.C126S) of the ASIP gene. Three missense mutations in the sheep MC1R gene cause the dominant black E(D) allele (p.M73K and p.D121N) and the putative recessive e allele (p.R67C). Here, we analysed these ASIP and MC1R mutations in 161 Massese sheep collected from four flocks. The presence of one duplicated copy allele including the ASIP gene was associated with grey coat colour (P = 9.4E-30). Almost all animals with a duplicated copy allele (37 out of 41) showed uniform apparent grey hair and almost all animals without a duplicated allele (117 out of 120) were completely black. Different forms of duplicated alleles were identified in Massese sheep including, in almost all cases, copies with exon 2 disrupting or partially inactivating mutations making these alleles different from the A(Wt) allele. A few exceptions were observed in the association between ASIP polymorphisms and coat colour: three grey sheep did not carry any duplicated copy allele and four black animals carried a duplicated copy allele. Of the latter four sheep, two carried the E(D) allele of the MC1R gene that may be the cause of their black coat colour. The coat colour of all other black animals may be determined by non-functional ASIP alleles (non-agouti alleles, A(a)) and in a few cases by the E(D) Extension allele. At least three frequent ASIP haplotypes ([D(5):g.5172T], [N:g.5172A] and [D(5):g.5172A]) were detected (organized into six different diplotypes). In conclusion, the results indicated that coat colours in the Massese sheep breed are mainly derived by combining ASIP and MC1R mutations.     

Mutations in the melanocortin 1 receptor (MC1R) gene are associated with coat colours in the domestic rabbit (Oryctolagus cuniculus)

We sequenced almost the complete coding region of the MC1R gene in several domestic rabbits (Oryctolagus cuniculus) and identified four alleles: two wild-type alleles differing by two synonymous single nucleotide polymorphisms (c.333A>G;c.555T>C), one allele with a 30-nucleotide in-frame deletion (c.304_333del30) and one allele with a 6-nucleotide in-frame deletion (c.280_285del6). A polymerase chain reaction-based protocol was used to distinguish the wild-type alleles from the other two alleles in 263 rabbits belonging to 37 breeds or strains. All red/fawn/yellow rabbits were homozygous for the c.304_333del30 allele. This allele represents the recessive e allele at the extension locus identified through pioneering genetic studies in this species. All Californian, Checkered, Giant White and New Zealand White rabbits were homozygous for allele c.280_285del6, which was also observed in the heterozygous condition in a few other breeds. Black coat colour is part of the standard colour in Californian and Checkered breeds, in contrast to the two albino breeds, Giant White and New Zealand White. Following the nomenclature established for the rabbit extension locus, the c.280_285del6 allele, which is dominant over c.304_333del30, may be allele E(D) or allele E(S).     

Genetic effects of stearoyl-coenzyme A desaturase (SCD) polymorphism on milk production traits in the Chinese dairy population

Stearoyl-CoA desaturase (SCD) is a multifunctional complex enzyme important in the cellular biosynthesis of fatty acids. The present study was to investigate the association of the SCD gene with milk production traits in dairy cattle. Two single nucleotide polymorphisms (SNPs) (g.6926A>G and g.8646A>G) in introns 3 and 4, and three SNPs (g.10153A>G, g.10213T>C and g.10329C>T) in exon 5 were identified with pooled DNA sequencing and genotyped using matrix-assisted laser desorption/ionization time of flight mass spectrometry assay in 752 Chinese Holstein cows. Polymorphism g.10329C>T was predicted to result in an amino acid replacement from alanine to valine in the SCD protein. With a mixed animal model, the significant associations of the five SNPs with 305-day milk, fat and protein yields and protein percentage were determined. We further demonstrated cows with heterozygous genotypes (A/G or C/T) had highest 305 day milk yield, fat yield, protein yield and lowest protein percentage. Heterozygous cows with genotype AG at the g.6926A>G locus showed the greatest milk yield (P < 0.0001), fat yield (P < 0.0001) and protein yield (P < 0.0001) among other heterozygous genotypes at any of the loci. Dominance effects of all identified SNPs on milk, fat and protein yields and protein percentage were significant. Moreover, significant allele substitution effects at g.6926A>G locus on milk yield and at g.10213T>C on protein yield were observed. Five-locus haplotypes and strong linkage disequilibrium (D' > 0.9) between the five SNPs were also observed. The results suggest that identified polymorphisms could be potential genetic markers to improve the production performance of Chinese Holstein.     

APOC3/A5 haplotypes, lipid levels, and risk of myocardial infarction in the Central Valley of Costa Rica

Genetic variation in the APOC3 and APOA5 genes has been associated with plasma triglyceride concentrations and may affect the risk of myocardial infarction (MI). To assess whether APOC3/A5 haplotypes are associated with risk of MI, we examined three single-nucleotide polymorphisms (SNPs) in APOC3 (3238C>G, -455T>C, and -482C>T) and six SNPs in the APOA5 gene (-1131T>C, c.-3A>G, c.56C>G, IVS3+476G>A, c.553G>T, and c.1259T>C) in incident cases (n = 1,703) of a first nonfatal MI matched for gender, age, and area of residence with population-based controls (n = 1,703). Conditional logistic regression models, adjusted for potential environmental confounders, were used for analysis. The common APOC3*222 haplotype was more frequent in cases than in controls (17.4% and 13.7%, respectively, P < 0.001) and was associated with increased risk of MI [odds ratio (OR) = 1.27; 95% confidence interval (95% CI), 1.09, 1.48] compared with APOC3*111 wild-type haplotype. This association was independent of the APOA5 SNPs. Although the APOC3 3238G, APOA5 -1131C, APOA5 c.-3G, and APOA5 c.1259C alleles were associated with higher triglyceride plasma concentrations, these effects could not explain the associations with MI in this population. In summary, this study supports the hypothesis that haplotypes in the APOC3 gene but not in the APOA5 gene increase susceptibility to MI.     

Melanocortin-4 receptor gene mutations in a Dutch cohort of obese children

The most common monogenic form of obesity is caused by mutations in the gene encoding the melanocortin-4 receptor (MC4R). We have screened the MC4R coding sequence in 291 patients of a Dutch outpatient pediatric obesity clinic. We analyzed the minimal promoter region of the gene in a random subgroup of 217 children. Our aims were (i) to determine the frequency of MC4R mutations in a cohort of Dutch clinically obese children and (ii) to search for mutations in the promoter of the gene. Eleven MC4R coding variants were detected. Five children had mutations that have been shown to affect receptor function by other research groups (p.Y35X, p.I251fs, p.G231S). These children did not have earlier onset of obesity or higher BMI-SDS than the remainder of the cohort. One child had a novel nonsynonymous coding mutation (p.L304F). This variant showed a markedly decreased cell surface expression in in vitro experiments and is thus expected to be pathogenic. We detected 12 variants in the MC4R flanking regions. Five of these were not previously described (c.-1101C>T, c.-705A>T, c.-461A>G, c.-312T>C, c.-213A>G). We investigated these mutations by family studies and a bioinformatic approach. We conclude that rare heterozygous mutations in the coding sequence of MC4R account for some severe obesity cases in the Dutch population. These patients are difficult to recognize in a clinical setting. We generated a list of all MC4R variants that were described in the literature so far, which can aid the interpretation of mutations found in a diagnostic setting.     

Base-pair neutral homozygotes can be discriminated by calibrated high-resolution melting of small amplicons

Genotyping by high-resolution melting analysis of small amplicons is homogeneous and simple. However, this approach can be limited by physical and chemical components of the system that contribute to intersample melting variation. It is challenging for this method to distinguish homozygous G::C from C::G or A::T from T::A base-pair neutral variants, which comprise approximately 16% of all human single nucleotide polymorphisms (SNPs). We used internal oligonucleotide calibrators and custom analysis software to improve small amplicon (42-86 bp) genotyping on the LightScanner. Three G/C (PAH c.1155C>G, CHK2 c.1-3850G>C and candidate gene BX647987 c.261+22,290C>G) and three T/A (CPS1 c.3405-29A>T, OTC c.299-8T>A and MSH2 c.1511-9A>T) human single nucleotide variants were analyzed. Calibration improved homozygote genotyping accuracy from 91.7 to 99.7% across 1105 amplicons from 141 samples for five of the six targets. The average T(m) standard deviations of these targets decreased from 0.067 degrees C before calibration to 0.022 degrees C after calibration. We were unable to generate a small amplicon that could discriminate the BX647987 c.261+22,290C>G (rs1869458) SNP, despite reducing standard deviations from 0.086 degrees C to 0.032 degrees C. Two of the sites contained symmetric nearest neighbors adjacent to the SNPs. Unexpectedly, we were able to distinguish these homozygotes by T(m) even though current nearest neighbor models predict that the two homozygous alleles would be identical.     

Identification of TDRP1 gene and its association with pig reproduction traits

This study was performed to identify and characterize the pig TDRP1 gene and to investigate its association with reproduction traits. The obtained pig TDRP1 cDNA (713 base pair [bp]) comprises a 561-bp open reading frame, which encodes a peptide of 187 amino acids. The identities of pig TDRP1 cDNA were 84.6%, 75.7%, and 77.4% with its counterparts in human, rat, and mice, respectively. Real-time polymerase chain reaction indicated that pig TDRP1 gene was highly expressed in pituitary of male and uterus of female animals. The pig TDRP1 gene contains three exons and two introns. A total of 13 single-nucleotide polymorphisms (SNPs) and 1 indel were identified in the screened partial genomic sequence, with most polymorphisms in introns. Allelic frequencies of five SNPs among eight pig breeds were further investigated, and it indicated that Landrace had the lowest genetic diversity. In Yorkshire, three SNPs (c.215+144T>C, c.215+249A>G, and c.215+672T>C) exhibited complete linkage disequilibrium in one haplotype block, and association analyses showed that all of them were significantly associated with number born alive of first parity (NBA1) (p<0.05). c.215+672T>C was also significantly associated with NBA6 (p<0.05). In addition, these three SNPs and two other ones (c.215+1001G>A and c.215+1026C>T) were associated with total born alive of second parity (TBA2) and TBA6 at the suggestive level (0.05相似文献   

Mutation in the melanocortin 1 receptor is associated with amber colour in the Norwegian Forest Cat

Amber (previously called X-Colour) is a yellow recessive coat colour observed in the Norwegian Forest Cat (NFC) population and apparently absent in other cat breeds. Until now, there has never been any scientific evidence of yellow recessive mutation ( e ) reported in the extension gene in Felidae. We sequenced the complete coding sequence region for the melanocortin 1 receptor in 12 amber, three carriers, two wild-type NFCs, one wild-type European Shorthair and two 'golden' Siberian cats and identified two single nucleotide polymorphisms (SNPs): a non-synonymous (FM180571: c.250G>A) and a synonymous (FM180571: c.840T>C) mutation. The c.250G>A SNP, further genotyped on 56 cats using PCR-RFLP, is associated with amber colour and only present in the amber cat lineages. It replaced an aspartic acid with a neutral polar asparagine in the second transmembrane helix (p.Asp84Asn), a position where e mutations have already been described. Three-dimensional models were built and showed electrostatic potential modification in the mutant receptor. With these results and together with those in the scientific literature, we can conclude that amber colour in NFCs is caused by a single MC1R allele called e , which has never been documented.     

Characterization of the effect of Melanocortin 1 Receptor,a member of the hair color genetic locus,in alpaca (Lama pacos) fleece color differentiation

Little is known about the inheritance and influence of the fleece color gene Melanocortin 1 Receptor (MC1R). Melanocortin 1 Receptor (MC1R) is a well-known gene responsible for red versus black fleece pigmentation and is hypothesized to be a candidate gene for variation in alpaca coloration patterns. Inheritance of red versus black pigmentation in the context of genetic mutation is well understood in many domesticated mammals. We characterized the MC1R gene in a population of multi-colored alpacas in order to better understand its effect on coat color in the alpaca. Our characterization of the alpaca MC1R gene revealed 11 mutations. Of these one is a 4 bp deletion, four are silent mutations and six are single nucleotide polymorphisms (SNPs) that alter the amino acid sequence (T28V, M87V, S126G, T128I, S196F, R301C). No mutation correlated completely with fleece color in alpacas at the MC1R locus. This may be due to the epistatic relationship of MC1R with other coat color genes especially agouti signaling protein (ASIP).     

DNA polymorphisms in bovine fatty acid synthase are associated with beef fatty acid composition

The objective of this study was to identify single nucleotide polymorphisms (SNPs) in the thioesterase (TE) domain of the bovine fatty acid synthase (FASN) gene and to evaluate the extent to which they were associated with beef fatty acid composition. The four exons in FASN that encode for the TE domain were sequenced, and three SNPs, AF285607:g.17924A>G, g.18663T>C and g.18727C>T, were identified. Purebred Angus bulls (n = 331) were classified into three genotype groups, g.17924AA (n = 121), g.17924AG (n = 168) and g.17924GG (n = 42). The g.17924A>G genotype was significantly associated with fatty acid composition of longissimus dorsi muscle of Angus bulls. Cattle with the g.17924GG genotype had lower myristic acid (C14:0; P < 0.0001), palmitic acid (C16:0, P < 0.05) and total saturated fatty acid contents (P < 0.01), greater health index (P < 0.001), oleic acid content (C18:1; P < 0.001) and total monounsaturated fatty acid concentration (P < 0.01) in the total lipids and triacylglycerols fraction than did those with the g.17924AA genotype. Because of the linkage disequilibrium between SNPs g.17924A>G and g.18663T>C, similar significant associations of fatty acid contents with the g.18663T>C genotypes were observed. In conclusion, the SNPs g.17924A>G and g.18663T>C may be used as DNA markers to select breeding stock that have a healthier fatty acid composition.     

Identification of a premature stop codon in the melanocyte-stimulating hormone receptor gene (MC1R) in Labrador and Golden retrievers with yellow coat colour

We have examined whether black/yellow coat colour in Labrador retrievers is controlled by allelic variants at the extension locus. As the gene encoding the melanocyte-stimulating hormone receptor (MC1R) has been shown to correspond to the extension locus in several species, we have determined the genomic MC1R sequence in Labrador retrievers with black and with yellow coat colour. Using primers based on the fox (Vulpes vulpes) MC1R sequence we initially isolated and sequenced the innerpart of the canine MC1R. By means of inverse PCR we succeeded in the characterization of both flanking regions of the MC1R gene (Genbank: AF064455). Comparison of the complete MC1R sequences of a yellow and a black Labrador retriever revealed a single C-->T mutation at nucleotide position 916 in the yellow dog. This transition changed the codon for arginine at position 305 into a stop codon, resulting in the elimination of the evolutionary strongly conserved 10 carboxyterminal amino acid residues. With an allele-specific-oligonucleotide (ASO) test it was shown that the mutation cosegregated with the recessively inherited yellow coat colour in the Labrador retriever. Golden retrievers also appeared to be homozygous for the mutation. Seventeen other breeds were all negative for the mutation. Since the Labrador and Golden retriever are closely related, we suggest a common founder for the yellow coat colour in Labrador and Golden retrievers.     

A new single nucleotide polymorphism in the rabbit (Oryctolagus cuniculus) myostatin (MSTN) gene is associated with carcass composition traits

This study aimed at the identification of genetic variations in the myostatin (MSTN) gene and testing their effects on carcass quality traits. We comparatively sequenced Giant Grey (GG) and New Zealand White (NZW) rabbits that were founders of a cross‐bred population. Alignment of our sequence data with the GenBank sequence of the rabbit MSTN gene (Ensembl Gene ID ENSOCUG00000012663) identified three single nucleotide polymorphisms (SNPs). The two novel SNPs (c.?125T>C, c.373+234G>A) and one known SNP (c.747+34C>T) were subsequently analysed for linkage with carcass composition traits in 363 F₂ animals of the cross GG × NZW. Significant linkage was found between c.373+234G>A and nine carcass composition traits (P < 0.05). No significant effects were found for c.?125T>C and c.747+34C>T. Because the linked SNP is located in intron 1 and no genetic variation was found in the coding region, further investigations are necessary to understand the functional effect of the c.373+234G>A variant on the variability of the traits.     

Non-synonymous polymorphisms in the human SLCO1B1 gene: an in vitro analysis of SNP c.1929A>C

Polymorphisms in the SLCO1B1 gene encoding the human hepatocellular uptake transporter OATP1B1 can be associated with alterations in transporter properties and may affect the pharmacokinetics of drugs transported by OATP1B1. Therefore, it is of interest to investigate newly identified genetic variations on their impact on the pharmacokinetic of OATP1B1 substrates. We analyzed the allelic frequencies of five variations (c.452A>G, c.1007C>G, c.1454G>T, c.1628T>G, and c.1929A>C) in Caucasians and investigated the influence of SNP c.1929A>C which had an allelic frequency of 4.7%. None of the 285 Caucasian DNA donors were carriers of c.452A>G, c.1007C>G, c.1454G>T, c.1628T>G. Liver samples carrying SNP c.1929A>C were analyzed for OATP1B1 protein expression demonstrating no differences in expression levels compared to wild-type samples. Possible functional consequences were analyzed using HEK cells stably expressing the mutated OATP1B1 protein (OATP1B1-Leu643Phe). Uptake experiments with sulfobromophthalein, estradiol-17ssD-glucuronide, pravastatin, and taurocholic acid showed no significant difference in the uptake kinetics compared to wild-type OATP1B1. We showed that four variations frequent in the Asian population were not detected in Caucasians and demonstrated that the frequent SNP c.1929A>C had no effect on the hepatic OATP1B1 protein expression and on the transport properties. Therefore, it is unlikely that c.1929A>C contributes to interindividual variability in drug disposition.     

Influence of the APOA5 locus on plasma triglyceride, lipoprotein subclasses, and CVD risk in the Framingham Heart Study

Several polymorphisms in the APOA5 gene have been associated with increased plasma triglyceride (TG) concentrations. However, associations between APOA5 and lipoprotein subclasses, remnant-like particles (RLPs), and cardiovascular disease (CVD) risk have been less explored. We investigated associations of five APOA5 single-nucleotide polymorphisms (SNPs; -1131T>C, -3A>G, 56C>G IVS3+ 476G>A, and 1259T>C) with lipoprotein subfractions and CVD risk in 1,129 men and 1,262 women participating in the Framingham Heart Study. Except for the 56C>G SNP, the other SNPs were in significant linkage disequilibria, resulting in three haplotypes (11111, 22122, and 11211) representing 98% of the population. SNP analyses revealed that the -1131T>C and 56C>G SNPs were significantly associated with higher plasma TG concentrations in both men and women. For RLP and lipoprotein subclasses, we observed gender-specific association for the -1131T>C and 56C>G SNPs. Female carriers of the -1131C allele had higher RLP concentrations, whereas in males, significant associations for RLPs were observed for the 56G allele. Moreover, haplotype analyses confirmed these findings and revealed that the 22122 and 11211 haplotypes exhibited different associations with HDL cholesterol concentrations. In women, the -1131C allele was associated with a higher hazard ratio for CVD (1.85; 95% confidence interval, 1.03-3.34; P = 0.04), in agreement with the association of this SNP with higher RLPs.