Cloning and sequence analysis of an extracellular serine-protease gene of Aeromonas hydrophila J-1

A pair of primers were designed according to the nucleotide sequences of the protease gene of Aeromonas species reported. With the specific primers, one target fragment about 900bp was amplified from Aeromonas hydrophila strain AhJ-1 genomic DNA via PCR. The PCR products were cloned into pGEM-T vector and sequenced. The sequence was compared with the corresponding regions of the GenBank strains and analyzed by DNAstar software. The nucleotide sequence showed 87 % homology to the sequence of Ahe2 gene. The nucleotide sequence was predicted to encode a 343-aa protein with the molecular weight of 35 700 and with high antigenicity. It suggested that the sequence of serine-protease gene can be used as a candidate fragment for DNA vaccine.