A Novel Metallothionein Gene from Mussel, Hyriopsis cumingii: Identification and Expression under Lanthanum Exposure

Metallothionein (MT) is a superfamily of cysteine-rich, metal-binding, low-molecular-weight proteins that participate in the storage, transportation, and metabolism of the trace metal elements. In this study, a novel MT gene from Hyriopsis cumingii was cloned (designated HcMT1); it shared 59.2% identity with previously published MT sequence of H. cumingii and 56.1-97.3% identity with other MT genes from mollusks. The expression level of HcMT1 in various tissues was determined by real-time polymerase chain reaction. Relatively higher expression levels were observed in digestive gonad, mantle, and gill, and the expression level in hemocytes was significantly upregulated by lanthanum (La3+) exposure. The nucleotide sequence of HcMT1 amplified from genomic DNA is identical to the cDNA template group under La3+ exposure, which indicated that HcMT1 is an intronless gene. These results indicate that HcMT1 may play an important role in La3+ metabolism.