Williams Valerie N, Reading Benjamin J, Amano Haruna, Hiramatsu Naoshi, Schilling Justin, Salger Scott A, Islam Williams Taufika, Gross Kevin, Sullivan Craig V
Department of Applied Ecology, College of Agriculture and Life Sciences of North Carolina State University, Raleigh, North Carolina.
J Exp Zool A Ecol Genet Physiol. 2014 Jul;321(6):301-15. doi: 10.1002/jez.1859. Epub 2014 Mar 20.
We quantified three vitellogenins (VtgAa, VtgAb, VtgC) or their derived yolk proteins (YPs) in the liver, plasma, and ovary during pre-vitellogenic (PreVG), mid-vitellogenic (MVG), and late-vitellogenic (LVG) oocyte growth and during post-vitellogenesis (PostVG) in the striped bass (Morone saxatilis) using label-free quantitative mass spectrometry (MS). Western blotting of the samples using antisera raised against gray mullet (Mugil cephalus) lipovitellins derived from VtgAa, VtgAb, and VtgC confirmed the MS results. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) revealed liver as the primary site of expression for all three Vtgs, with extra-hepatic transcription weakly detected in ovary, foregut, adipose tissue, and brain. Quantitative real-time RT-PCR confirmed vtgAb to be primarily expressed in liver and VtgAb proteins were predominant in liver and plasma from MVG to PostVG. However, the primary period of deposition into oocytes of VtgAb occurred up until MVG, whereas VtgAa was primarily deposited from MVG to LVG. The VtgC was gradually taken up by oocytes throughout vitellogenesis and was detected at trace levels in plasma. The ratio of yolk proteins derived from VtgAa, VtgAb, VtgC (YPAa/YPAb/YPC) in PostVG ovary is 1.4:1.4:1, which differs from ratios previously reported for other fish species in that YPC comprises a greater proportion of the egg yolk. Our results indicate that proportional accumulation of multiple Vtgs in the yolk may depend both on the precise rates of their hepatic secretion and specific uptake by oocytes. Furthermore, composition of the Vtg-derived yolk may vary among Acanthomorph fishes, perhaps reflecting their different early life histories and reproductive strategies.
我们使用无标记定量质谱法(MS),对条纹鲈(Morone saxatilis)在卵黄发生前期(PreVG)、卵黄发生中期(MVG)和卵黄发生后期(LVG)的卵母细胞生长过程以及卵黄发生后期(PostVG)期间肝脏、血浆和卵巢中的三种卵黄蛋白原(VtgAa、VtgAb、VtgC)或其衍生的卵黄蛋白(YPs)进行了定量分析。使用针对源自VtgAa、VtgAb和VtgC的鲻鱼(Mugil cephalus)脂卵黄蛋白产生的抗血清对样品进行蛋白质免疫印迹分析,证实了质谱分析结果。半定量逆转录聚合酶链反应(RT-PCR)显示,肝脏是所有三种Vtgs的主要表达部位,在卵巢、前肠、脂肪组织和大脑中微弱检测到肝外转录。定量实时RT-PCR证实vtgAb主要在肝脏中表达,并且VtgAb蛋白在从MVG到PostVG的肝脏和血浆中占主导地位。然而,VtgAb进入卵母细胞的主要沉积期一直持续到MVG,而VtgAa主要从MVG沉积到LVG。VtgC在整个卵黄发生过程中逐渐被卵母细胞摄取,并在血浆中检测到痕量水平。PostVG卵巢中源自VtgAa、VtgAb、VtgC的卵黄蛋白比例(YPAa/YPAb/YPC)为1.4:1.4:1,这与先前报道的其他鱼类物种的比例不同,因为YPC在蛋黄中所占比例更大。我们的结果表明,卵黄中多种Vtgs的比例积累可能既取决于它们在肝脏中的精确分泌速率,也取决于卵母细胞的特定摄取。此外,Vtg衍生的卵黄组成在棘鳍鱼类中可能有所不同,这可能反映了它们不同的早期生活史和繁殖策略。