Molecular characterization of toll-like receptor 2 gene in Bikaneri camels (Camelus dromedarius)

Toll -like receptors (TLRs) are an important family of receptors constituting the first line of defense system. Toll -like receptors play crucial roles in the innate immune system by recognizing pathogen-associated molecular patterns derived from various microbes. Present investigation was carried out to characterize the coding sequence of TLR2 gene in Indian dromedary camels. Blood was collected from five Bikaneri camels and genomic DNA was isolated. Eight pairs of overlapping primers were designed for amplification of TLR2 gene coding region. All the fragments were successfully amplified using Polymerase chain reaction (PCR). The PCR products were purified and subjected to Sanger's sequencing. TLR2 gene fragment of 3213 bp consisting of 2287 bp of coding sequence of exon 2 and 926 bp of 3'untranslated region (UTR) was successfully amplified. The sequence generated was submitted to the NCBI with accession number MW557315.1. The encoded amino acids codes for 12 leucine rich repeats (LRR) (Accession no. UBN09134.1). At the nucleotide level, the Bikaneri camels' TLR2 gene showed highest similarity with camelids (99.30 to 99.59%) followed by vicugna pacos (97.54%). The nucleotide sequence similarity was lowest with Homo sapiens (82.37%). The amino acid sequence based phylogenetic tree revealed close relationship between camelid species followed by pig (86.2%), whereas human, gorilla, horse and donkey were distantly placed on the tree.