Diz Angel P, Dudley Edward, MacDonald Barry W, Piña Benjamin, Kenchington Ellen L R, Zouros Eleftherios, Skibinski David O F
Institute of Life Sciences, School of Medicine, Swansea University, Swansea SA2 8PP, West Glamorgan, Wales, United Kingdom.
Mol Cell Proteomics. 2009 Jan;8(1):132-44. doi: 10.1074/mcp.M800237-MCP200. Epub 2008 Sep 15.
Study of the genetic basis of gene expression variation is central to attempts to understand the causes of evolutionary change. Although there are many transcriptomics studies estimating genetic variance and heritability in model organisms such as humans there is a lack of equivalent proteomics studies. In the present study, the heritability underlying egg protein expression was estimated in the marine mussel Mytilus. We believe this to be the first such measurement of genetic variation for gene expression in eggs of any organism. The study of eggs is important in evolutionary theory and life history analysis because maternal effects might have profound effects on the rate of evolution of offspring traits. Evidence is presented that the egg proteome varies significantly between individual females and that heritability of protein expression in mussel eggs is moderate to high suggesting abundant genetic variation on which natural selection might act. The study of the mussel egg proteome is also important because of the unusual system of mitochondrial DNA inheritance in mussels whereby different mitochondrial genomes are transmitted independently through female and male lineages (doubly uniparental inheritance). It is likely that the mechanism underlying this system involves the interaction of specific egg factors with sperm mitochondria following fertilization, and its elucidation might be advanced by study of the proteome in females having different progeny sex ratios. Putative identifications are presented here for egg proteins using MS/MS in Mytilus lines differing in sex ratio. Ontology terms relating to stress response and protein folding occur more frequently for proteins showing large expression differences between the lines. The distribution of ontology terms in mussel eggs was compared with those for previous mussel proteomics studies (using other tissues) and with mammal eggs. Significant differences were observed between mussel eggs and mussel tissues but not between the two types of eggs.
基因表达变异的遗传基础研究是理解进化变化原因的核心。尽管有许多转录组学研究估计了人类等模式生物中的遗传方差和遗传力，但缺乏等效的蛋白质组学研究。在本研究中，我们估计了海洋贻贝Mytilus卵蛋白表达的遗传力。我们认为这是对任何生物体卵中基因表达的遗传变异进行的首次此类测量。卵的研究在进化理论和生活史分析中很重要，因为母体效应可能对后代性状的进化速率产生深远影响。有证据表明，个体雌性之间的卵蛋白质组存在显著差异，贻贝卵中蛋白质表达的遗传力为中度到高度，这表明存在丰富的遗传变异，自然选择可能会作用于此。贻贝卵蛋白质组的研究也很重要，因为贻贝中线粒体DNA遗传的特殊系统，即不同的线粒体基因组通过雌性和雄性谱系独立传递（双单亲遗传）。该系统的潜在机制可能涉及受精后特定卵因子与精子线粒体的相互作用，通过研究具有不同后代性别比例的雌性的蛋白质组可能会推进对其的阐明。本文使用串联质谱法（MS/MS）对性别比例不同的Mytilus品系的卵蛋白进行了推定鉴定。对于品系间表达差异较大的蛋白质，与应激反应和蛋白质折叠相关的本体术语出现得更为频繁。将贻贝卵中的本体术语分布与之前贻贝蛋白质组学研究（使用其他组织）以及哺乳动物卵的分布进行了比较。观察到贻贝卵与贻贝组织之间存在显著差异，但两种类型的卵之间没有差异。
