Diapause regulation and stress tolerance in artemia embryos: gene expression, protein function and metabolism

甲壳类动物Artemia franciscana的胚胎可以发育成游动的幼虫，也可以被囊化并进入滞育，这是一种以发育停滞和代谢活性大大降低为特征的生理状态。被包裹的胚胎具有极强的抗压力能力，即使在环境温度下补水，它们也能在高温、干燥和多年的缺氧中存活下来。因此，被包裹的青蒿胚胎代表了地球上最抗压力的后生动物生命形式之一。蒿胚在滞育发育过程中表现出不同的基因表达，产生起始所需的蛋白质。维持并可能终止滞育。这项工作的长期目标是阐明青蒿胚胎调节滞育特异性发育的细胞、分子和生化机制，并确定胚胎如何在生理应激下存活。短期目标包括鉴定在滞育期间上调的基因和确定其蛋白质项目的功能。特别感兴趣的是大量的分子伴侣，如滞育特异性小热休克蛋白和铁蛋白同源物阿耳特敏。其他有趣的蛋白质的例子包括那些介导细胞内信号通路的蛋白质，这些信号通路影响代谢活动、细胞生长和分裂以及基因转录。调节滞育终止的蛋白质变化，一个几乎未被触及的领域，也将被确定。这些结果将有助于我们了解真核细胞在发育和暴露于压力时的基本过程。所获得的信息将在医学上有潜在的应用，因为小热休克蛋白功能的扰动会导致疾病。此外，许多经历滞育的昆虫通过它们作为害虫的角色影响农业和林业，而蒿在水产养殖中作为饲料来源具有重要作用。

Embryos of the crustacean, Artemia franciscana, may develop into swimming larvae or they may encyst and enter diapause, a physiological state characterized by developmental arrest and greatly reduced metabolic activity. Encysted embryos are extremely stress tolerant and they survive high temperature, desiccation and years of anoxia even when hydrated at ambient temperature. As such, encysted Artemia embryos represent one of the most stress resistant metazoan life forms on earth. Artemia embryos exhibit differential gene expression during diapause-destined development which yields proteins required for initiation. maintenance and perhaps termination of diapause. The long term objectives of the work are to elucidate cell, molecular and biochemical mechanisms by which Artemia embryos regulate diapause-specific development and to determine how embryos survive physiological stress. Short term objectives include the identification of genes that are up-regulated during diapause and determining the functions of their protein projects. Of particular interest are abundant molecular chaperones such as the diapause-specific small heat shock proteins and the ferritin homologue artemin. Other examples of interesting proteins include those mediating intracellular signalling pathways which influence metabolic activity, cell growth and division, and gene transcription. Protein changes that regulate diapause termination, a field that is almost untouched, will also be identified. The results will contribute to our apreciation of fundamental processes in eukaryotic cells during development and upon exposure to stress. The information obtained will have potential applications in medicine as perturbation of small heat shock protein function leads to disease. Additionally, many insects that undergo diapause influence agriculture and forestry through their roles as pests and Artemia has an important role as a source of feed in aquaculture.