Small heat shock protein gene expression and function in xenopus

健康的细胞需要合成和维持正确折叠的蛋白质。环境压力和疾病状态会扰乱这种情况，如果不加以控制，可能导致细胞死亡。小热休克蛋白（sHsps）是一类分子伴侣蛋白，在细胞内稳态和蛋白质折叠中发挥重要作用，并保护细胞免受多种应激，包括热休克和暴露于重金属、活性氧和亚砷酸盐。在细胞应激过程中，sHsps作为分子伴侣，与变性蛋白结合，抑制其聚集，并在有利条件恢复后促进其重新折叠。此外，sHsp的合成或突变与多种疾病有关，如癌症、多发性硬化症、各种神经病变和肌肉肌病。在过去的23年里，申请人实验室一直在积极研究sHsp基因在模式蛙系统非洲爪蟾中的表达和功能。他们在sHsp家族Hsp30的表达和功能表征方面取得了重大进展。最近，他们报道了另一种爪蟾sHsp Hsp27的存在及其分子伴侣功能，Hsp27是人类Hsp27的同源物。申请人研究计划的长期目标是了解爪蟾sHsps的调控和功能。这项拨款建议的具体目标是：1)分析Hsp30基因表达的发育调控机制，2)表征Hsp30和Hsp27的分子伴侣结构域，3)确定热休克爪蟾胚胎中Hsp30和Hsp27缺失的影响，4)检测蛋白酶体抑制对培养细胞和胚胎中sHsp基因表达的影响，5)表征镉对培养爪蟾细胞和胚胎中Hsp30和Hsp27基因表达的影响。这项假设驱动的研究计划将建立在先前的工作基础上，探索与sHsp基因表达和功能相关的新领域。了解sHsp的结构和功能将有助于更好地理解各种疾病状态。

Healthy cells require the synthesis and maintenance of correctly folded proteins. Environmental stresses and disease states can perturb this situation and if left unchecked could result in cell death. Small heat shock proteins (sHsps) are a class of molecular chaperones that play important roles in cellular homeostasis and protein folding as well as protecting the cell against numerous stresses including heat shock and exposure to heavy metals, reactive oxygen species and arsenite. During cellular stress, sHsps, in their role as molecular chaperones, bind to denatured protein, inhibit their aggregation, and facilitate their refolding once favorable conditions have returned. Also, sHsp synthesis or mutations have been associated with various diseases such as cancer, multiple sclerosis, various neuropathologies and muscle myopathy. Over the past 23 years, the applicant's laboratory has been actively researching sHsp gene expression and function in the model frog system, Xenopus laevis. They have made significant progress in the characterization of expression and function of the sHsp family, Hsp30. Recently, they reported on the presence and molecular chaperone function of a second Xenopus sHsp, Hsp27, a human Hsp27 homolog. The long term goals of the applicant's research program are to understand the regulation and function of Xenopus sHsps. The specific aims of this grant proposal are to: 1) analyze the mechanism(s) associated with developmental regulation of Hsp30 gene expression, 2) characterize the molecular chaperone domains of Hsp30 and Hsp27, 3) determine the effect of Hsp30 and Hsp27 depletion in heat shocked Xenopus embryos, 4) examine the effect of proteasomal inhibition on sHsp gene expression in cultured cells and embryos, and 5) characterize the effect of cadmium on Hsp30 and Hsp27 gene expression in Xenopus cultured cells and embryos. This hypothesis-driven research proposal will build on previous work and explore new areas related to sHsp gene expression and function. Knowledge regarding sHsp structure and function will provide a better understanding of various disease states.