Heat shock genes and the response to environmental stress during zebrafish development.

斑马鱼发育过程中的热休克基因和对环境应激的反应。

• 批准号: RGPIN-2014-03725
• 负责人: Krone, Patrick
• 金额: $ 2.99万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610615
• 关键词: Heat; shock; genes; response; environmental

Heat shock proteins are expressed in cells following exposure to environmental stress such as elevated temperature or toxic metals, and help cells survive these periods of stress. Several hsps also play important roles as molecular chaperones that normally help other proteins fold and reach their correct destination in the cell. It is important for a cell to be able to regulate where, when, and how much a heat shock protein is expressed, and it does this largely be regulating the expression of the gene that codes for the hsp. Toxic metals such as mercury and cadmium are a significant concern, and have negative effects on developing embryos. Mercury causes a range of problems, including visual defects in both humans and fish. Cadmium can damage the olfactory organ of both humans and fish, causing a loss of the sense of smell. A major question regarding toxic metals is whether they accumulate more in some cells and tissues than others, and whether the chemical form of the metal affects this process. Our work uses the zebrafish embryo as a model to examine the effects of environmental stress on development. Zebrafish are a popular model system since much of their development occurs in a similar way to human development, in addition to being an excellent model to look at fish development itself. We have used synchrotron x-rays to examine where in zebrafish embryos the toxic metal mercury accumulates. We found that one of the major targets is cells of sensory systems, in particular parts of the eye, olfactory organ, and a specialized sensory organ in fish known as the lateral line. We have also examined a specific heat shock protein known as hsp70. Interestingly, hsp70 is expressed normally during eye development, and is required for normal eye formation. This gene is also expressed in both the olfactory organ and lateral line following exposure to another toxic metal, cadmium. Experiments in this proposal will examine the impact of exposing zebrafish embryos to different types of mercury, and whether the cells that take up large amounts of mercury are also the most sensitive. This will include looking at whether cells in the sensory organs are more prone to death, and whether the proper function of the organs is disrupted. We will also examine how the hsp70 gene is turned on and off in mercury and cadmium treated embryos, and during normal development of the eye lens. Some of the work will use a transgenic fish model we have developed that fluoresces bright green in cells that express hsp70, allowing for very rapid detection of stressed cells. In summary, the work will allow us to develop an integrated model of how regulation of the hsp70 is gene is fine-tuned during normal development and following exposure of embryos to environmental stress, and how this relates to other events occurring in target cells ranging from toxic metal uptake and accumulation to functional defects in target organs. This work will be important to our understanding of how cells in an embryo respond to and survive exposure to environmental stress at the molecular and cellular level. We will be able to correlate impacts on sensory cells and their function with i) the actual amount of a toxic metal in these cells, ii) how the hsp70 gene is activated in response to this stress, and iii) how this activation may assist embryonic cells in surviving the stress event. It will also allow us to develop a better understanding of how the hsp70 gene is expressed during normal development of the eye, and further elucidate the importance of this event. This work will further determine if our transgenic fish strain can be used as a rapid fluorescent predictor of negative outcomes in some sensory organs.

热休克蛋白在暴露于环境压力（例如高温或有毒金属）后在细胞中表达，并帮助细胞在这些压力时期生存。一些热休克蛋白还作为分子伴侣发挥重要作用，通常帮助其他蛋白质折叠并到达细胞中的正确目的地。对于细胞来说，能够调节热休克蛋白的表达地点、时间和程度非常重要，这在很大程度上是通过调节热休克蛋白编码基因的表达来实现的。 汞和镉等有毒金属是一个值得关注的问题，并对发育中的胚胎产生负面影响。汞会引起一系列问题，包括人类和鱼类的视觉缺陷。镉会损害人类和鱼类的嗅觉器官，导致嗅觉丧失。关于有毒金属的一个主要问题是，它们在某些细胞和组织中是否积累得比其他细胞和组织更多，以及金属的化学形式是否会影响这一过程。 我们的工作使用斑马鱼胚胎作为模型来研究环境压力对发育的影响。斑马鱼是一种流行的模型系统，因为它们的大部分发育都以与人类发育相似的方式发生，此外，斑马鱼也是研究鱼类发育本身的优秀模型。我们使用同步加速器 X 射线来检查有毒金属汞在斑马鱼胚胎中积聚的位置。我们发现主要目标之一是感觉系统细胞，特别是眼睛、嗅觉器官和鱼类的一种特殊感觉器官（称为侧线）。我们还检查了一种称为 hsp70 的特定热休克蛋白。有趣的是，hsp70 在眼睛发育过程中正常表达，并且是正常眼睛形成所必需的。在接触另一种有毒金属镉后，该基因也在嗅觉器官和侧线中表达。 该提案中的实验将研究将斑马鱼胚胎暴露于不同类型汞的影响，以及吸收大量汞的细胞是否也是最敏感的。这将包括观察感觉器官中的细胞是否更容易死亡，以及器官的正常功能是否受到破坏。我们还将研究 hsp70 基因在汞和镉处理的胚胎中以及眼睛晶状体正常发育过程中如何打开和关闭。其中一些工作将使用我们开发的转基因鱼模型，该模型在表达 hsp70 的细胞中发出亮绿色荧光，从而可以非常快速地检测应激细胞。总之，这项工作将使我们能够开发一个综合模型，说明 hsp70 基因的调节在正常发育过程中和胚胎暴露于环境应激后如何进行微调，以及它与靶细胞中发生的其他事件（从有毒金属的吸收和积累到靶器官的功能缺陷）之间的关系。 这项工作对于我们了解胚胎中的细胞如何在分子和细胞水平上应对环境压力并在环境压力下存活下来非常重要。我们将能够将对感觉细胞及其功能的影响与i）这些细胞中有毒金属的实际含量，ii）hsp70基因如何响应这种压力而激活，以及iii）这种激活如何帮助胚胎细胞在压力事件中生存联系起来。它还将使我们能够更好地了解hsp70基因在眼睛正常发育过程中如何表达，并进一步阐明这一事件的重要性。这项工作将进一步确定我们的转基因鱼品系是否可以用作某些感觉器官负面结果的快速荧光预测因子。