Molecular cloning, characterization and expression analysis of the pigeon toll-like receptor 7 gene

【Objective】 To clone and characterize the pigeon Toll like receptor 7 (TLR7) gene.【Method】RT-PCR,RACE (rapid amplification of cDNA ends),Quantitative real-time PCR and bio-informatics software was used in this study.【Result and conclusion】 The study showed that the full-length of pigeon TLR7 cDNA sequence was 3 516 bp with the longest open reading frame (ORF) of 3 175 bp encoding a peptide of 1 048 amino acids. The deduced amino acid sequence of pigeon TLR7 contained three main structural domains including an extracellular leucine rich repeats domains(LRRs),a transmembrane domain (TM) and a Toll/IL-1 receptor domain(TIR); pigeon TLR7 shared amino acid sequence similarity with the Anser cygnoides TLR7 gene, Anas platyrhynchos TLR7 gene, Gallus gallus TLR7 gene (above 78%), mammal TLR7 gene(about 60%), and fish TLR7 gene (less than 55%).Quantitative real-time PCR analysis revealed that the pigeon TLR7 mRNA widespread expression in the tested tissues was high in small intestine, spleen, kidney and low in brain，lung, trachea, heart, pancreas, muscle and skin. In this study TLR7 gene has been isolated from pigeon, cloned and its main functional domains have been predicted.