The Cloning And Sequence Analysis Of The CDNA Of Reindeer β-Defensin-1(reBD-1)

Defensins are a kind of positive antimicrobial peptides, which are an important component in innate immunity of organism and contain cysteine-rich and distribute abroad in the kingdoms of animal and plant. According to the differences of the position and connect manner of cysteines, the property of precursors, the position of expression, defensins are devided into five subfamilies:α-defensin,β-defensin,θ-defensin, insect defensin and plant defensin.β-defensins express extensively in the epithelial tissues of many organs in mammals, human and aves.In this study, total RNA after isolation from tougue epithelia of a reindeer was reverse transcribed to synthesize the middle of reindeerβ-defensin (reBD-1) cDNA using primers designed by taking conserved region of ruminant′sβ–defensin cDNA sequences.Then, we synthesize successfully the full-length cDNA of reindeerβ-defensin (reBD-1) using RACE (Rapid Amplification of cDNA Ends).372 bp of the full-length cDNA of reBD-1 contain a ORF of 192 bp, an 5′untranslated region (5′UTR) of 44 bp, an 3′UTR of 118 bp and ploy(A)15.The ORF encode an prepro-reBD-1 of 64 amino acid residues, which include a signal peptide of 20 amino acid residues, a propiece of 6 amino acid residues, a muture peptide of 38 amino acid residues. The muture peptide was predicted that contain 10 positive amino acid residues (6 Arginine-R, 3 Lysine-K, 1 Histidine-H) and not found any negative amino acid residues. Therefore, the reBD-1 is a positive peptide.Nucleotide and amino acid sequence homology analysis indicated that reBD-1 share the highest homology with theβ-defensins of cow, secondary with camel, goat and sheep, lower with human and pig. Both nucleotide and amino acid sequence homology shows that evolutionalary relationship of reBD-1 is closer to theβ-defensins of ruminant than human and pig.