PCR-cloning of goldfish and tilapia metallothionein complementary DNAs.

Metallothionein (MT) is believed to be a sensitive and effective "biomarker" for monitoring metal contamination in fish. Comparison of amino acid sequences between flounder MT and trout MT revealed that there is a conserved region at their N-terminals. Using oligonucleotides derived from this conserved region, reverse transcription- polymerase chain reaction (RT-PCR) was performed to obtain MT complementary DNAs (cDNAs) from goldfish, Carassius auratus, and tilapia, Tilapia mossambica. These cDNA probes would be useful in developing sensitive PCR-based methods to detect MT gene expression for monitoring metal pollution in local waters.