A New Beta Defensin from Sika Deer: Molecular Cloning and Sequence Characterization

Abstract

The beta-defensins are small, well-characterized peptides with broad antimicrobial activities. Here we report the identification of a novel β-defensin, sika deer β-defensin-1 (siBD-1), from sika deer tissues with a pair of PCR primers according to the conserved cDNA sequences of known ruminant β-defensins. Total RNA was extracted from the tongue epithelia of a sika deer and the 418 bp cDNA encoding siBD-1 was amplified by the reverse transcription PCR (RT-PCR), 5′- and 3′-RACE. The cDNA contained an open reading frame (ORF) of 192 bases which encoded a 64 amino acid prepro-peptide. The prepro-peptide contained six invariantly spaced cysteine residues, which is the β defensin consensus sequence. The putative mature peptide of the siBD-1 contained nine positively charged residues (5 arginine-R, 3 lysine-K, and 1 histidine-H). The sequence homology shows that siBD-1 has 73.0–90.6% amino-acid identity and 74.6–90.6% cDNA identity with other ruminant beta-defensins, sharing the greatest identity with buffalo enteric β-defensin in both amino acid and nucleotide sequences.

Keywords:

• Antimicrobial peptide
• β-Defensin
• Sika deer

Acknowledgments

We thank the deer ranch in ShengLe Economic Zone of BaoTou city in China for supplying all tissue samples. Thanks also to the innovative team project of Inner Mongolia Agricultural University for providing financial assistance (NDPYTD2010-6).