Cloning and expression of avian beta defensin 7 gene from chicken

A pairs of primers used in polymerase chain reaction (PCR) was designed following the NM_001001194 from GenBank to amplify the beta defensin 7 gene of chicken. The total RNA was isolated from spinal cord cells of chicken，and the first cDNA strand was obtained by approach of reverse transcription PCR. The products of PCR were linked with T plasmid vectors，and then transformed into Escherichia coli（E. Coli） DH5α strain cells subsequently. Expressional plasmid vector，pET32a-gal7，was reconstructed with restriction endonuclease Hind Ⅲ and BamH I. Recombinant plasmid vector，pET32a-gal7，was induced with Isopropyl- β-D-Thiogalacto Pyranoside (IPTG) in E. Coli DE3 strain cells to produce recombinant Gal7 protein. The results showed that the cloned cDNA sequence of beta defensin 7 gene of chicken was comprised of 132 nucleotide acid residues，and encoded the beta defensin 7 with 44 amino acids and predicted molecular weight 4923.81Da. The identity to NM_001001194 is 99%. The recombinant peptides had strong antibacterial activity against staphylococcus aureus in vitro.