mRNA expression of a cadmium-responsive gene is a sensitive biomarker of cadmium exposure in the soil collembolan Folsomia candida.
The gene expression of environmental organisms is useful as a biomarker of environmental pollution. One of its advantages is high sensitivity. We identified the cDNA of a novel cadmium-responsive gene in the soil collembolan Folsomia candida. The deduced protein, designated "metallothionein-like motif containing protein" (MTC), was cysteine-rich and contained a metallothionein-like motif with similarity to metallothionein, but had a much longer sequence than metallothionein and contained repeated sequences of amino acids. Expression of MTC mRNA was sensitively induced by cadmium exposure at 0.3 mg/kg of dry food, a concentration at which toxic effects are not observed, but expression was not affected by gamma-ray exposure (an inducer of oxidative stress). These findings suggest that MTC is involved in cadmium-binding processes rather than in oxidative-stress responses. In conclusion, we suggest that gene expression of MTC may be a candidate biomarker for detecting low levels of cadmium contamination in soil.
Nakamori
Taizo
T
Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan. taizo@ynu.ac.jp
Fujimori
Akira
A
Kinoshita
Keiji
K
Ban-nai
Tadaaki
T
Kubota
Yoshihisa
Y
Yoshida
Satoshi
S
D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D015870:Gene Expression / Q000187:drug effects*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007313:Insecta / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism / Q000633:toxicity*
D015415:Biomarkers; D019476:Insect Proteins; D012333:RNA, Messenger; D012989:Soil Pollutants; D002104:Cadmium