Embryo Defenses Against Toxins

Epel 96-04354 这项为期一年的拨款将资助一个试点项目，旨在了解胚胎如何保护自己免受环境毒素的侵害。Epel博士假设P-糖蛋白药物转运蛋白提供这种保护，作为第一道防线将毒素排除在细胞之外。它存在于一种泥栖蠕虫尾刺线虫的胚胎和成虫中，其活性可保护其胚胎免受添加的测试毒素的侵害。这种保护可能是刺海胆胚胎在孔隙水（泥滩沉积物的上层海水）中正常发育的原因。 海星和海胆的胚胎没有这种转运蛋白，它们的胚胎不能在泥滩的孔隙水中发育。如果这种药物转运蛋白确实能保护胚胎，那么在海胆或海星的胚胎中表达这种转运蛋白应该能保护它们免受环境毒素的侵害。这项为期一年的试点研究的主要目标是使用从小鼠或线虫中克隆的基因在海星或海胆卵母细胞中表达这种转运蛋白，并确定所产生的胚胎是否会发育。如果是这样的话，那么就可以提出和回答大量关于这种转运蛋白在保护胚胎方面的作用以及在一般海洋环境中保护免受毒素侵害的问题。 这种转运蛋白在海洋环境中并不普遍存在，我们有限的调查表明，它存在于过滤器和悬浮饲料，但不是在海胆或海星。我们希望在这项试点研究中解决的第二个问题涉及这种转运蛋白的分布。它存在于一种生活在沉积物中的echiuroid蠕虫中。拥有这种传送器是不是echiuroid的一般属性？或者它是某种仅限于生活方式使它们暴露于毒素的动物（如沉积物居住或过滤器喂养）？为了回答这个问题，这项试点研究的一个小组成部分将确定运输蛋白是否在生活在清洁栖息地或具有不同生活方式的该组成员中表达或过度表达。 提供这两个问题的答案，特别是关于在棘皮动物胚胎中克隆的转运蛋白基因的表达的信息，将表明将表明在胚胎中使用表达的基因的研究方法的可行性。这些方法，如果可行的话，将提供严格的信息，一般的生物学胚胎防御机制，特别是这种药物转运蛋白的作用

Epel 96-04354 This one year grant will fund a pilot project aimed at understanding how embryos defend themselves against environmental toxins. Dr. Epel hypothesizes that the P-glycoprotein drug transporters provide this protection, acting as a first line of defense to keep toxins out of the cell. It is present in embryos and adults of a mud-dwelling worm, Urechis caupo, and its activity protects its embryos against added test toxins. This protection might account for the ability of Urechis embryos to develop normally in pore water (the supernatant sea water from the mud flat sediments). The embryos of starfish and sea urchins do not possess this transporter and their embryos cannot develop in pore water from the mud flats. If this drug transporter in fact protects embryos, then expression of the transporter in the embryos of the sea urchin or starfish should confer protection against environmental toxins. The major goal of this one year pilot study is to express this transporter, using the gene cloned from the mouse or nematode worm, in starfish or sea urchins oocytes and to determine if the resultant embryos will develop. If so, a large number of questions can then be asked and answered about the role of this transporter in protection of embryos and also about protection against toxins in the marine environment in general. This transporter is not ubiquitous in the marine environment, and our limited survey indicates its presence in filter and suspension feeders but not in sea urchins or starfish. A second question we wish to address in this pilot study relates to the distribution of this transporter. It is present in an echiuroid worm which lives in sediments. Is having this transporter a general attribute of being an echiuroid? Or is it something restricted to animals whose lifestyle exposes them to toxins (such as sediment dwelling or filter feeding)? To provide an answer to this question, a minor component of this pilot study will determine whether the transport protein is ex pressed or over expressed in members of this group that live in clean habitats or have different lifestyles. Providing answers to these two questions, especially information about the expression of the cloned transporter gene in echinoderm embryos, will indicate will indicate the feasibility of research approaches using expressed genes in embyros. These approaches, if feasible, would provide rigorous information on the biology of embryo defense mechanisms in general and the role of this drug transporter in particular