Yilmaz Ozlem, Prat Francisco, Ibáñez A Jose, Köksoy Sadi, Amano Haruna, Sullivan Craig V
Akdeniz University, Fisheries Faculty, Antalya, 07070, Turkey.
Instituto de Ciencias Marinas de Andalucía, Consejo Superior de Investigaciones Científicas, Avda. República Saharaui 2, 11510 Puerto Real, Cádiz, Spain.
Comp Biochem Physiol B Biochem Mol Biol. 2016 Apr-May;194-195:71-86. doi: 10.1016/j.cbpb.2015.11.010. Epub 2015 Nov 28.
Three complete vitellogenin (Vtg) polypeptides of European sea bass (Dicentrarchus labrax), an acanthomorph teleost spawning pelagic eggs in seawater, were deduced from cDNA and identified as VtgAa, VtgAb and VtgC based on current Vtg nomenclature and phylogeny. Label free quantitative mass spectrometry verified the presence of the three sea bass Vtgs or their product yolk proteins (YPs) in liver, plasma and ovary of postvitellogenic females. As evidenced by normalized spectral counts, VtgAb-derived protein was 2- to 5-fold more abundant, depending on sample type, than for VtgAa, while VtgC-derived protein was less abundant, albeit only 3-fold lower than for VtgAb in the ovary. Western blotting with Vtg type-specific antisera raised against corresponding gray mullet (Mugil cephalus) lipovitellins (Lvs) detected all three types of sea bass Vtg in the blood plasma of gravid females and/or estrogenized males and showed that all three forms of sea bass Lv undergo limited partial degradation during oocyte maturation. The comparatively high levels of VtgC-derived YPs in fully-grown oocytes and the maturational proteolysis of all three types of Lv differ from what has been reported for other teleosts spawning pelagic eggs in seawater but are similar to recent findings for two species of North American Moronidae, the striped bass (Morone saxatilis) and white perch (Morone americana), which spawn pelagic and demersal eggs, respectively in fresh water. Together with the high Vtg sequence homologies and virtually identical structural features of each type of Vtg between species, these findings indicate that the moronid multiple Vtg systems do not substantially vary with reproductive environment.
欧洲海鲈（Dicentrarchus labrax）是一种在海水中产浮性卵的棘鳍总目硬骨鱼，从其cDNA中推导得到了三种完整的卵黄蛋白原（Vtg）多肽，并根据当前的Vtg命名法和系统发育将其鉴定为VtgAa、VtgAb和VtgC。无标记定量质谱法证实，在卵黄生成后期雌性的肝脏、血浆和卵巢中存在这三种海鲈Vtg或其产物卵黄蛋白（YP）。根据标准化光谱计数可知，取决于样品类型，VtgAb衍生的蛋白比VtgAa丰富2至5倍，而VtgC衍生的蛋白含量较少，尽管在卵巢中仅比VtgAb低3倍。用针对相应鲻鱼（Mugil cephalus）卵黄脂磷蛋白（Lv）产生的Vtg类型特异性抗血清进行的蛋白质印迹法，在妊娠雌性和/或经雌激素处理的雄性的血浆中检测到了所有三种类型的海鲈Vtg，并表明所有三种形式的海鲈Lv在卵母细胞成熟过程中都经历了有限的部分降解。在完全成熟的卵母细胞中，VtgC衍生的YP水平相对较高，并且所有三种类型的Lv在成熟过程中都发生了蛋白水解，这与其他在海水中产浮性卵的硬骨鱼的报道不同，但与最近对两种北美尖吻鲈科鱼类的研究结果相似，条纹鲈（Morone saxatilis）和白鲈（Morone americana）分别在淡水中产浮性卵和沉性卵。这些发现连同物种间每种Vtg的高Vtg序列同源性和几乎相同的结构特征表明，尖吻鲈科的多个Vtg系统不会因生殖环境而发生实质性变化。
