Cloning, characterization and TBT exposure response of CuZn superoxide dismutase from Haliotis diversicolor supertexta.

The full-length cDNA and genomic DNA of a cytoplasmic copper, zinc superoxide dismutase (CuZn-sod) were cloned from the hepatopancreas of small abalone Haliotis diversicolor supertexta by RT-PCR, RACE and TAIL PCR. The full-length cytoplasmic CuZn-sod cDNA (designated sasod) comprises 984 bp. Its ORF encodes a polypeptide of 154 amino acids with a predicted molecular mass of 15.7 kDa and theoretical isoelectric point of 6.30. The deduced amino acid (designated saSOD) shares a common consensus pattern with the SODs of vertebrate and invertebrate animals. The full-length sasod genomic DNA comprises 5,574 bp, containing five exons and four introns. The splice donor and acceptor sequence of the four introns is 5'GT-AG3'. Real time quantitative PCR analysis revealed that sasod expression level in hepatopancreas of small abalone was no significant difference at 2, 6, 48 and 192 h post TBT exposure (P > 0.05). However, the sasod expression level at 12 and 24 h post TBT exposure was decreased significantly (P < 0.05).