Cloning and prokaryotic expression of BnADC gene from Brassica napus L.

An arginine decarboxylase gene ADC,named BnADC,was isolated by homologous cloning and RACE technology using fresh bud of Brassica napus L.cv Zhongshuang 6.The full cDNA was 2 649bp including 344bp of 5′-UTR,226bp of 3′-UTR and 2 079bp of an open reading frame(ORF).Also a small uORF encoding four amino acids,as MIRE,was found in 5′-UTR.Amino acid homology analysis indicated that BnADC protein was highly homologous to other ADC proteins which had 93% identity to that of Brassica juncea.Phylogenetic tree analysis revealed that BnADC was more related to those of Arabidopsis thaliana and B.juncea.Based on the full cDNA of BnADC,a fusion expression vector pET30a(+)-BnADC was constructed,then transformed into Escherichia coli strain BL21(DE3).SDS-PAGE electrophoresis analysis showed an 81.1kD fusion protein produced,which was mainly in the deposition of transformed E.coli debris.