Polymorphisms in TAS2R38 and the taste bud trophic factor, gustin gene co-operate in modulating PROP taste phenotype.

The PROP taste phenotype varies greatly among individuals, influencing eating behavior and therefore may play a role in body composition. This variation is associated with polymorphisms in the bitter receptor gene TAS2R38 and the taste-bud trophic factor gustin gene. The aim of this study was to examine the relationship between TAS2R38 haplotypes and the gustin gene polymorphism rs2274333 in modulating PROP taste phenotype. PROP phenotype was determined in seventy-six volunteers (29 males, 47 females, age 25±3 y) by scaling methods and threshold measurements. TAS2R38 and gustin gene genotyping was performed using PCR techniques. The lowest responsiveness in PROP nontasters is strongly associated with the AVI nontasting TAS2R38 variant and the highest responsiveness in supertasters is strongly associated to allele A and genotype AA of the gustin gene. These data support the hypothesis that the greater sensitivity of supertasters could be mediated by a greater taste-bud density. Polymorphisms in TAS2R38 and gustin gene, together, accounted for up to 60% of the phenotypic variance in PROP bitterness and to 40% in threshold values. These data, suggest that other unidentified factors may be more relevant for detecting low concentrations of PROP. Moreover, the presence of the PAV variant receptor may be important for detecting high concentrations of PROP, whereas the presence of allele A in gustin polymorphism may be relevant for perceiving low concentrations. These data show how the combination of the TAS2R38 and gustin gene genotypes modulate PROP phenotype, providing an additional tool for the evaluation of human eating behavior and nutritional status.

Calò C ，Padiglia A ，Zonza A ，Corrias L ，Contu P ，Tepper BJ ，Barbarossa IT ... -  《-》

The gustin (CA6) gene polymorphism, rs2274333 (A/G), is associated with fungiform papilla density, whereas PROP bitterness is mostly due to TAS2R38 in an ethnically-mixed population.

PROP responsiveness is associated with TAS2R38 haplotypes and fungiform papilla density. Recently, we showed that a polymorphism in the gene coding for the salivary trophic factor, gustin (CA6), affects PROP sensitivity by acting on cell growth and fungiform papillae maintenance, in a genetically homogeneous cohort. Since population homogeneity can lead to over estimation of gene effects, the primary aim of the present work was to confirm gustin's role in PROP bitterness intensity and fungiform papillae density in a genetically diverse population. Eighty subjects were genotyped for both genes by PCR techniques. PROP responsiveness was assessed by a filter paper method and fungiform papilla density was determined in each subject. As expected, PROP bitterness ratings were lower in individuals with the AVI/AVI diplotype of TAS2R38 than in individuals with PAV/PAV and PAV/AVI diplotypes. However, no differences in PROP bitterness among genotypes of the gustin gene, and no differences in the density of fungiform papillae related to TAS2R38 diplotype were found. In contrast, the density of fungiform papillae decreased as the number of minor (G) alleles at the gustin locus increased. In addition, the distribution of TAS2R38 genotypes within each gustin genotype group showed that the occurrence of recessive alleles at both loci was infrequent in the present sample compared to other populations. These findings confirm that papillae density is associated with gustin gene polymorphism, rs2274333 (A/G), in an ancestrally heterogeneous population, and suggest that variations in the frequency of allele combinations for these two genes could provide a salient explanation for discrepant findings for gustin gene effects across populations.

Barbarossa IT ，Melis M ，Mattes MZ ，Calò C ，Muroni P ，Crnjar R ，Tepper BJ ... -  《-》

The gustin (CA6) gene polymorphism, rs2274333 (A/G), as a mechanistic link between PROP tasting and fungiform taste papilla density and maintenance.

Melis M ，Atzori E ，Cabras S ，Zonza A ，Calò C ，Muroni P ，Nieddu M ，Padiglia A ，Sogos V ，Tepper BJ ，Tomassini Barbarossa I ... -  《PLoS One》

Supertasting and PROP bitterness depends on more than the TAS2R38 gene.

Hayes JE ，Bartoshuk LM ，Kidd JR ，Duffy VB ... -  《CHEMICAL SENSES》

Variation in the bitter-taste receptor gene TAS2R38, and adiposity in a genetically isolated population in Southern Italy.

Tepper BJ ，Koelliker Y ，Zhao L ，Ullrich NV ，Lanzara C ，d'Adamo P ，Ferrara A ，Ulivi S ，Esposito L ，Gasparini P ... -  《Obesity》