Molecular cloning, phylogenetic analysis and developmental expression of a vitellogenin (Vg) gene from the intertidal copepod Tigriopus japonicus.
Vitellogenin (Vg) is the precursor of egg yolk protein vitellins, which serve as energy resource for embryonic development. Vg measurement has been used as a biomarker of exposure to endocrine-disrupting chemicals (EDCs). Therefore, Vg gene structure has been identified from several species used in environmental monitoring of EDCs. Among the copepods, except from the salmon louse, there is no report on Vg genes or their products. By using molecular cloning, we determined the full Vg gene sequence from the intertidal copepod, Tigriopus japonicus. The full cDNA sequence was of 5692 bp containing 5529 bp of open reading frame (ORF) encoding for 1842 amino acids. The phylogenetic analysis revealed that T. japonicus Vg is distinct from the other arthropods as it formed a clade with salmon louse only. The expression of Vg transcripts was negligible in nauplii; detectable only at the copepodid stage 3. Females expressed over 270 times more Vg transcripts than males. The promoter sequence of T. japonicus Vg gene revealed an estrogen receptor (ER) half site and a metal response element (MRE). When copepods were exposed to trace metals, cadmium after 96 h exposure caused significantly higher induction of Vg transcripts. Taken together, molecular analysis of T. japonicus Vg would be helpful in understanding its role in development. Previous studies have established T. japonicus as a potential model for testing of endocrine-disrupting chemicals (EDCs). The study of T. japonicus Vg will fuel momentum in using this species in comparative molecular endocrinology and biomonitoring of EDCs.
Lee
Kyun-Woo
KW
National Research Lab of Marine Molecular and Environmental Bioscience, Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
Hwang
Dae-Sik
DS
Rhee
Jae-Sung
JS
Ki
Jang-Seu
JS
Park
Heum Gi
HG
Ryu
Jae-Chun
JC
Raisuddin
Sheikh
S
Lee
Jae-Seong
JS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D033342:Copepoda / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014131:Trace Elements / Q000494:pharmacology; D014819:Vitellogenins / Q000145:classification / Q000235:genetics* / Q000378:metabolism
D014131:Trace Elements; D014819:Vitellogenins