Molecular characterization and expression of vitellogenin (Vg) genes from the cyclopoid copepod, Paracyclopina nana exposed to heavy metals.
Induction of vitellogenin (Vg) has been used as a biomarker of exposure to heavy metals and endocrine-disruption chemicals (EDCs) in aquatic organisms. Here, we identified the full-length Vg1 and Vg2 sequence from the brackish water copepod, Paracyclopina nana. Vg1 gene contained 5718bp of the open reading frame (ORF) that encoded the putative protein of 1905 amino acids residues, while Vg2 gene consisted of 5442bp of ORF, encoding the putative protein of 1813 amino acids residues. P. nana Vgs showed highly conserved domains in the N-terminal region. The phylogenetic analysis revealed that P. nana Vgs are distinct from other arthropods, such as insects and decapods, as it formed a clade with other copepods, Tigriopus japonicus and salmon louse (Lepeophtheirus salmonis). The expression of Vg transcripts was detectable after the copepodid stages 4-5. Female copepods expressed over 83 times and 223 times more Vg1 and Vg2 transcripts, respectively, than males. When copepods were exposed to heavy metals (0.1mg/L Cd, 0.4mg/L Cu, and 2mg/L AsIII) for 24, 48, 72, and 96h, P. nana Vg transcripts were highly induced in a time-dependent manner. Interestingly, Vg2 gene was more susceptible than Vg1 to trace heavy metal exposure. This finding indicates that P. nana Vgs provide a potential indicator for assessing the toxic effect of heavy metals. In addition, we suggest P. nana as a potential model species for risk-assessment to environmental pollutants in brackish water.
Hwang
Dae-Sik
DS
Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea.
Lee
Kyun-Woo
KW
Han
Jeonghoon
J
Park
Heum Gi
HG
Lee
Jehee
J
Lee
Young-Mi
YM
Lee
Jae-Seong
JS
D020121:5' Untranslated Regions; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D033342:Copepoda / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D018076:DNA, Complementary / Q000737:chemistry; D020224:Expressed Sequence Tags; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005796:Genes; D008297:Male; D019216:Metals, Heavy / Q000633:toxicity; D008969:Molecular Sequence Data; D008970:Molecular Weight; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D023382:Toxicity Tests, Acute; D015533:Transcriptional Activation / Q000187:drug effects; D014819:Vitellogenins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*
D020121:5' Untranslated Regions; D018076:DNA, Complementary; D019216:Metals, Heavy; D021382:Protein Sorting Signals; D014819:Vitellogenins