Transcript variations, phylogenetic tree and chromosomal localization of porcine aryl hydrocarbon receptor (AhR) and AhR nuclear translocator (ARNT) genes.

Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor best known for mediating xenobiotic-induced toxicity. AhR requires aryl hydrocarbon receptor nuclear translocator (ARNT) to form an active transcription complex and promote the activation of genes which have dioxin responsive element in their regulatory regions. The present study was performed to determine the complete cDNA sequences of porcine AhR and ARNT genes and their chromosomal localization. Total RNA from porcine livers were used to obtain the sequence of the entire porcine transcriptome by next-generation sequencing (NGS; lllumina HiSeq2500). In addition, both, in silico analysis and fluorescence in situ hybridization (FISH) were used to determine chromosomal localization of porcine AhR and ARNT genes. In silico analysis of nucleotide sequences showed that there were two transcript variants of AhR and ARNT genes in the pig. In addition, computer analysis revealed that AhR gene in the pig is located on chromosome 9 and ARNT on chromosome 4. The results of FISH experiment confirmed the localization of porcine AhR and ARNT genes. In the present study, for the first time, the full cDNAs of AhR and ARNT were demonstrated in the pig. In future, it would be interesting to determine the tissue distribution of AhR and ARNT transcript variants in the pig and to test whether these variants are associated with different biological functions and/or different activation pathways.