Phylogenetic and Protein Domain Architecture Analysis of Toll- like Receptor 4-10 Genes in Camel (Camelus dromedarius)

Toll-like receptors (TLRs) are evolutionary conserved protein and most extensively studied pathogen recognition receptors (PRRs) which provoke innate immune responses after recognition of invading pathogens. The present research is the first report of determination of domain architecture of camel (camelus dromedarius) TLRs4-10 proteins by Simple Modular Domain Architecture (SMART) tool. The study revealed that all the TLR proteins showed the typical structure containing Leucine Reach Repeats (ectodomain), transmembrane domain (TM), Toll/interleukin-1 receptor (TIR) domains except for TLR9 which was devoid of TM domain. The TLR 7,8,9 possessed more Leucine Rich Repeats (LRRs) motifsin their ectodomains than the other TLRs (4, 5, 6, 10).Further, the TM domain in TLRs (4-10) was exactly of similar length. However, the TIR domain was constituted of almost equal number of amino acids (140-144aa). Based on a phylogenetic analysis of the camel TLRs (1-10), the intracellularly expressed genes TLR7, TLR8 and TLR9 were clustered together whereas extracellularly expressed TLR1, 2, 6, and 10 branched out close to each other.