Molecular Cloning and Characterization of the Expression Profiles of Vitellogenin Transcripts in the Dojo Loach (Misgurnus anguillicaudatus) in Response to 17α-Ethinylestradiol and 17β-Estradiol Administration

Abstract

The gene, vitellogenin (vtg) was cloned and characterized in the dojo loach (Misgurnus anguillicaudatus), an indigenous freshwater species in East Asia, in order to develop tools for detecting the effects of estrogenic endocrine-disrupting chemicals (EEDCs). Full-length cDNAs encoding seven distinct vtg transcripts (vtg1-7) were obtained. The corresponding deduced amino acid sequences (Vtg1-7) were divided into two types; type I (Vtg1-6; 89-99% identical), which contained both lipovitellin (Lv) and phosvitin (Pv), and type II (Vtg7), which contained Lv alone. Phylogenetic analysis revealed that the type I and type II Vtgs in the loach could be classified as VtgAo1 and VtgC types, respectively. Immuno-biochemical analyses using type-specific Vtg antisera revealed that VtgAo1 proteins appeared to be the major Vtg type in this species. Males were administered (aqueous exposure) either 17β-estradiol (E2) or 17α-ethinylestradiol (EE2), the results from which were used to determine that hepatic vtgAo1 expression was estrogen-sensitive. The precise classification of the loach vtg/Vtg products, as well as their induction profiles following the estrogenic stimulation, provide a basis for their use as sensitive biomarkers when EEDC activities are evaluated in the freshwater environments in East Asia.

Vitellogenesis and choriogenesis in fishes

“…In both cases, VtgC orthologues exist in addition to these paralogous VtgAs [24]. Figure 3 shows a molecular phylogenetic tree of amino acid sequences deduced from Vtg gene transcripts constructed by Finn and Kristoffersen [93], with some additional insights obtained through our research [60, [94][95][96]. It should be noted that more recent analyses of Vtg gene synteny have raised new questions concerning the relative importance of WGD versus TGD in the evolution of fish Vtgs and the timing of these duplications [97,98], and indicate that the A-type and C-type Vtgs have a much longer evolutionary history (BP ~ 425 million) than previously thought.…”

Proposing Effective Ecotoxicity Test Species for Chemical Safety Assessment in East Asia: A Review

“…In genetic toxicity analysis, dichlorvos, flufiprole, copper sulfate, mitomycin C and Trichloroethylene caused DNA strand break to the liver cell, chromosomal aberration increase, micronucleus rate increase [ 33 , 81 , 82 , 86 ]. In response to progesterone, phenanthrene, 17β-estradiol (E2), 17α-ethinylestradiol (EE2), flufiprole, Venlafaxine (VFX), o-desmethylvenlafaxine (OVFX), glyphosate, H 2 O 2 , M. anguillicaudatus exhibited significant changes of endocrine disruption and development process disturbance, oxidative stress, neurotoxicity, cellular mortality, cellular structure changes, apoptosis occurrence [ 33 , 82 , 87 , 88 , 89 , 90 , 91 ].…”