Abstract

GENETIC VARIATIONS OF THE AS2R38 BITTER TASTE RECEPTOR GENE; BIOINFORMATICS APPROACH

Dr. Hassan Sadek, PhD*, Asma Khalfan Al Maashari, Aiysha Yaqoob Al Jabri, Bushra Said Al Abri, Hajer Abdullah Al Madhani, Zakiya Majed Al Hashmi and Zainab Al Amri

Abstract

Background: Having a bitter taste in the mouth while consuming something bitter, like black coffee is expected. Having a bitter taste for long period of time in the mouth, regardless of what been eating or drinking, is not normal and can indicate of several health conditions. There are different ways in the human body to protect against disease and dangerous components. The ability to identify bitterness is considered as one of these essential ways. There is a bitter taste receptor in humans encoded by the TAS2R38 gene. This receptor has the ability to manage the bitterness perception and to differentiate between nutritive and harmful components. The variation is highly affected by the taste and by genetic variation of chemosensory receptors depending on the level of allelic variation across species and across human populations. Our systematic review discusses 4 points related to the TAS2R38 gene including the aversion to vegetables and sweet/fat, smoking behaviors, Gastric cancer, and eating behavior. Method: by using NCBI databases, specifically GenBank to analyze DNA sequence and mRNA sequence of TAS2R38 gene. GenBank file format was helpful to extract an accession number of the gene, number of amino acids, number of intron and exons and length of nucleotide. FASTA format was also useful to retrieve the nucleotide sequence and get the function of the protein. BLAST used to compare protein product of TAS2R38 gene between human and western lowland gorilla. Results: The accession number of the TAS2R38 gene was NC_000007.14, number of exons found was one and the gene located in chromosome 7. This gene encodes a seven transmembrane G protein-Coupled receptor. PTC and PROP have been identified as ligands for this receptor. Taster and non-taster are two common allelic forms of this gene. These alleles differ at three nucleotide positions resulting in different protein (A49P, A262V, and V2961) with amino acid combination PAV identifying the taster variant and AVI identifying non-taster variant. Dog, rat, cow, and mouse are organisms that have the same gene. Conclusion: TAS2R38 haplotype were not associated with adiposity among both gender. The carrot was only the vegetable related to the TAS2R38 gene. Among smokers and non-smokers, there was no difference in the frequency of the TAS2R38 gene. There is no significant difference in dietary intake among TAS2R38 diplotype but this gene can play a role in gastric carcinogenesis. There is no association between TAS2R38 genotype and eating behavior (hunger and restraint) but there is an association between gene and decrease disinhibition.

Keywords: TAS2R38 gene, smokers, dietary intake, eating behavior, adiposity and vegetable.