Abstract
In this study we report the sequences of MT-2 cDNA from two species of Megascoleidae earthworms, Metaphire posthuma and Polypheretima elongata, by mRNA differential display after exposure of the organisms to cadmium. Complementary (c)DNA was verified as the MT-2 gene by the characteristics of its predicted translation product, namely a high cysteine content, conserved CXC motifs, and a molecular weight of around 8 kDa. Amino acid sequence alignment revealed a conserved TKCCG in the cloned MT-2 of both megascolecid earthworms instead of the corresponding conserved TQCCG found in lumbricid earthworms. The cDNAs corresponding to the two megascolecid MT-2 genes were expressed, and the MT-2 proteins were purified for biochemical characterization. The binding of Cu2+ exhibited monophasic kinetics and those of Zn2+ and Cd2+ biphasic kinetics. The proteins bound more tightly to Cd2+ than to Zn2+ and more tightly still to Cu2+. Zn-MT and apo-MT were the most effective at scavenging free radicals, followed by Cd-MT. In conclusion, MT-2s from M. posthuma and P. elongata showed unique sequence features compared to those of lumbricid earthworms. These earthworms could be used to evaluate heavy-metal pollution in soil due to the inducible MT-2 by cadmium exposure.
| Original language | English |
|---|---|
| Pages (from-to) | 349-357 |
| Number of pages | 9 |
| Journal | Comparative Biochemistry and Physiology - C Toxicology and Pharmacology |
| Volume | 149 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2009 Apr 1 |
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All Science Journal Classification (ASJC) codes
- Physiology
- Biochemistry
- Toxicology
- Cell Biology
- Health, Toxicology and Mutagenesis
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Cloning, expression, and characterization of cadmium-induced metallothionein-2 from the earthworms Metaphire posthuma and Polypheretima elongata. / Liang, Shih Hsiung; Jeng, Yu Ping; Chiu, Yun-Wen; Chen, Jiun Hong; Shieh, Bao Sen; Chen, Chien Yen; Chen, Chien Cheng.
In: Comparative Biochemistry and Physiology - C Toxicology and Pharmacology, Vol. 149, No. 3, 01.04.2009, p. 349-357.Research output: Contribution to journal › Article
TY - JOUR
T1 - Cloning, expression, and characterization of cadmium-induced metallothionein-2 from the earthworms Metaphire posthuma and Polypheretima elongata
AU - Liang, Shih Hsiung
AU - Jeng, Yu Ping
AU - Chiu, Yun-Wen
AU - Chen, Jiun Hong
AU - Shieh, Bao Sen
AU - Chen, Chien Yen
AU - Chen, Chien Cheng
PY - 2009/4/1
Y1 - 2009/4/1
N2 - In this study we report the sequences of MT-2 cDNA from two species of Megascoleidae earthworms, Metaphire posthuma and Polypheretima elongata, by mRNA differential display after exposure of the organisms to cadmium. Complementary (c)DNA was verified as the MT-2 gene by the characteristics of its predicted translation product, namely a high cysteine content, conserved CXC motifs, and a molecular weight of around 8 kDa. Amino acid sequence alignment revealed a conserved TKCCG in the cloned MT-2 of both megascolecid earthworms instead of the corresponding conserved TQCCG found in lumbricid earthworms. The cDNAs corresponding to the two megascolecid MT-2 genes were expressed, and the MT-2 proteins were purified for biochemical characterization. The binding of Cu2+ exhibited monophasic kinetics and those of Zn2+ and Cd2+ biphasic kinetics. The proteins bound more tightly to Cd2+ than to Zn2+ and more tightly still to Cu2+. Zn-MT and apo-MT were the most effective at scavenging free radicals, followed by Cd-MT. In conclusion, MT-2s from M. posthuma and P. elongata showed unique sequence features compared to those of lumbricid earthworms. These earthworms could be used to evaluate heavy-metal pollution in soil due to the inducible MT-2 by cadmium exposure.
AB - In this study we report the sequences of MT-2 cDNA from two species of Megascoleidae earthworms, Metaphire posthuma and Polypheretima elongata, by mRNA differential display after exposure of the organisms to cadmium. Complementary (c)DNA was verified as the MT-2 gene by the characteristics of its predicted translation product, namely a high cysteine content, conserved CXC motifs, and a molecular weight of around 8 kDa. Amino acid sequence alignment revealed a conserved TKCCG in the cloned MT-2 of both megascolecid earthworms instead of the corresponding conserved TQCCG found in lumbricid earthworms. The cDNAs corresponding to the two megascolecid MT-2 genes were expressed, and the MT-2 proteins were purified for biochemical characterization. The binding of Cu2+ exhibited monophasic kinetics and those of Zn2+ and Cd2+ biphasic kinetics. The proteins bound more tightly to Cd2+ than to Zn2+ and more tightly still to Cu2+. Zn-MT and apo-MT were the most effective at scavenging free radicals, followed by Cd-MT. In conclusion, MT-2s from M. posthuma and P. elongata showed unique sequence features compared to those of lumbricid earthworms. These earthworms could be used to evaluate heavy-metal pollution in soil due to the inducible MT-2 by cadmium exposure.
UR - http://www.scopus.com/inward/record.url?scp=60949109009&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=60949109009&partnerID=8YFLogxK
U2 - 10.1016/j.cbpc.2008.09.004
DO - 10.1016/j.cbpc.2008.09.004
M3 - Article
C2 - 18834958
AN - SCOPUS:60949109009
VL - 149
SP - 349
EP - 357
JO - Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology
JF - Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology
SN - 1532-0456
IS - 3
ER -