Molecular characterization and differential mRNA expression profiling of Toll-like receptor-2 gene in Vechur (Bos indicus) and crossbred (Bos indicus X Bos taurus) cattle of Kerala in response to anthrax vaccination

Abstract

Toll like receptors (TLRs) are type 1 transmembrane proteins expressed in almost all cell types and activate the innate immune system. The present study involved characterization and differential transcriptional expression profiling of Toll-like receptor-2 gene in Vechur (Bos indicus) and crossbred (Bos indicus X Bos taurus) cattle of Kerala in response to anthrax vaccination. Sequence analysis revealed 2355 bp long TLR2 open reading frame encoding 784 amino acids with a signal peptide of 20 amino acid residues. The sequence of Vechur TLR2 revealed 96–99% identity with other ruminant species. At amino acid level, 94–99% similarity was observed with other livestock species. Seven nucleotide variations were observed when compared with other Indian cattle and 17 variations with Bos taurus. The five non-synonymous mutations observed in Vechur as compared to Bos indicus (GenBank Acc. No. EU413951.1) were p.Gln149Pro, p.Ile335Thr, p.Lys.337Arg, p.Ser345Asn and p.Met605Thr. The eight non synonymous variations observed as compared to Bos taurus (GenBank Acc. No. NM174197.2) were p.Asp63Glu, p.Gly68Ser, p.Ile111Val, p.Phe127Leu, p.His326Gln, p.Asn417Ser, p.Arg563His and p.His665Gln. This is the first report about the full-length cDNA sequence and the single nucleotide variations of TLR2 gene of the Vechur cattle, the smallest cattle of the world. The prolonged upregulation of TLR2 mRNA in Vechur cattle as compared to Crossbred cattle post anthrax vaccination is suggestive of the greater immune response of this native cattle as compared to exotic cattle.