Multiple vitellogenins and their unique roles in marine teleosts

Multiple piscine vitellogenins: biomarkers of fish exposure to estrogenic endocrine disruptors in aquatic environments

“…Induction ratios between Vg-530 and Vg-320 also varied with the reproductive status of female goby. Both types of Vg were found at fairly equal but low levels (~ 1 μg per ml serum or less) in the plasma of wild female goby during the non-reproductive season; however, Vg-530 appeared to be dominant in the serum of vitellogenic females (Ohkubo et al, 2003).…”

“…It was suggested that the presence of small peptides and free amino acids (FAAs) generated during FOM-associated proteolysis of the yolk proteins contributes, at least in part, to the acquisition of an osmotic gradient necessary for uptake of water (oocyte hydration), resulting in neutrally buoyant eggs (reviews: Patiño and Sullivan, 2002;Hiramatsu et al, 2002a;Matsubara et al, 2003;Romano et al, 2004). The dual Vg system of the barfin flounder is currently the best known example of specific physiological mechanisms underlying this phenomenon.…”

“…The second cleavage of Vg-derived yolk proteins occurs in oocytes of marine teleosts during FOM as described in the previous section, but this process is not typical of fish that spawn demersal eggs (termed benthophils). The second proteolysis is possibly mediated by several physiological events, including acidification of yolk and activation of lysosomal enzymes (reviews: Hiramatsu et al, 2002a;Matsubara et al, 2003;Polzonetti-Magni et al, 2004;Romano et al, 2004). The enzymes responsible for FOM-associated proteolysis have been identified in only a few species.…”

“…However, most current methods of evaluating and interpreting the effects of estrogenic EDCs using Vg as a biomarker are based on acceptance of the outdated "single Vg" model of piscine oogenesis, either intentionally or due to a failure to keep pace with current research on vitellogenin multiplicity. Recent cDNA cloning and immunobiochemical investigations have confirmed that the presence of multiple forms of Vg is the norm in most species of fishes examined to date (reviewed by Hiramatsu et al, 2002a;Patiño and Sullivan, 2002;Matsubara et al, 2003;Hiramatsu et al, 2005). Thus, there is strong potential for misuse of Vg-based assays for assessing the impact of EDCs because the target type of Vg gene or protein and its sensitivity to estrogen induction is usually unknown for the species under investigation and may differ between assay systems and even between laboratories performing assays on the same species.…”

Purification and characterization of a novel incomplete-type vitellogenin protein (VgC) in Sakhalin taimen (Hucho perryi)

“…This simple model in which one molecule of teleost Vg gives rise to three yolk proteins has been referred to as the "single Vg" model (see Hiramatsu et al, 2002cHiramatsu et al, , 2005. However, recent gene cloning and immunobiochemical analyses have confirmed that the presence of multiple forms of Vg in fish is entirely normal, leading to the adoption of a new "multiple Vg model" for teleost oocyte growth (reviews: Hiramatsu et al, 2002cHiramatsu et al, , 2005Hiramatsu et al, , 2006Patiño and Sullivan 2002;Matsubara et al, 2003). As described in Hiramatsu et al (2002cHiramatsu et al ( , 2005, members of advanced teleost taxa (Paracanthopterygii and Acanthopterygii) generally express three types of Vg at the transcription level, two of which (classified as VgA and VgB by Hiramatsu et al, 2005Hiramatsu et al, , 2006; VgAa and VgAb by Finn and Kristoffersen, 2007) have been referred to as a "complete" Vg form based on their complete structure with regard to yolk protein domains (Lv, Pv, and β'-c).…”