EXPRESSION & FUNCTION OF ORGANELLE HEAT SHOCK PROTEINS

大多数真核和原核细胞对高温做出反应 以及与热休克的产生有关的某些其他压力 蛋白质(HSPs)。热休克蛋白是进化上保守的蛋白质 被认为是在压力下生存所必需的，或者 从压力中恢复。热休克蛋白功能也是已知的参与 在正常的细胞生长和发育中。就在最近，它是 发现特定的热休克蛋白定位于半自主真核生物 细胞器、线粒体和叶绿体。这些细胞器 热休克蛋白与先前在 胞质或胞核。我已经克隆了这个基因并对其进行了测序 同源的21 kDa核编码叶绿体HSP 真核细胞胞质低分子量热休克蛋白。我也有过 鉴定出两个高分子量(63和100 kDa)叶绿体 热休克蛋白。拟议的研究将检查表达和 21 kDa叶绿体热休克蛋白的功能，并进一步鉴定 63 kDa和100 kDa叶绿体热休克蛋白。我们的长期目标是 在分子水平上确定细胞器热休克蛋白的功能， 并更好地了解它们在细胞生理学中的作用 真核生物对环境的反应。 互补的分子、生物化学和遗传方法将 用于研究细胞器热休克蛋白的作用。生物化学 热休克蛋白21的性质及其与其他蛋白质的相互作用 将检查细胞器的分布。热休克蛋白21的表达 信使核糖核酸和蛋白质将在一系列生理学的 在应激条件下和正常发育期间。作为额外的 测定细胞器热休克蛋白致突变功能的方法 拟南芥植物种群将被筛选以鉴定HSP21 有缺陷的突变体。这些突变体的表型将被检测。 在正常生长和高温胁迫期间。的研究 将启动63 kDa和100 kDa热休克蛋白，包括克隆和 对相应的DNA进行测序。 综上所述，细胞器定位的热休克蛋白的产生是一种新的 已发现的应激反应分量和正常 真核细胞发育计划。建议进行的研究 随着我们对细胞的这一基本方面的进一步了解 生物化学。

Most eukaryotic and prokaryotic cells respond to high temperature and certain other stresses with the production of heat shock proteins (HSPs). The HSPs are evolutionarily conserved proteins hypothesized to be essential for survival during stress, or recovery from stress. HSP functions are also known to participate in normal cell growth and development. Very recently, it has been found that specific HSPs are localized to semiautonomous eukaryotic organelles, the mitochondria and chloroplasts. These organelle HSPs are homologous to previously characterized HSPs found in the cytoplasm or nucleus. I have cloned and sequenced the gene for a major, 21 kDa nuclear-encoded chloroplast HSP which is homologous to eukaryotic cytoplasmic low molecular weight HSPs. I have also identified two high molecular weight (63 and 100 kDa) chloroplast HSPs. The proposed research will examine the expression and function of the 21 kDa chloroplast HSP, and further characterize the 63 and 100 kDa chloroplast HSPs. Our long term goals are to determine the function of organelle HSPs at the molecular level, and to better understand their role in the cellular physiology of eukaryotic responses to the environment. Complementary molecular, biochemical and genetic approaches will be used to investigate the role of organelle HSPs. The biochemical properties of HSP21, its interaction with other proteins and intra- organelle distribution will be examined. The expression of HSP21 mRNA and protein will be studied under a range of physiological stress conditions and during normal development. As an additional approach to determining organelle HSP function, mutagenized population of Arabidopsis plants will be screened to identify HSP21 deficient mutants. The phenotype of these mutants will be examined during both normal growth and high temperature stress. Studies of the 63 and 100 kDa HSPs will be initiated, including cloning and sequencing of corresponding cDNAs. In summary, the production of organelle-localized HSPs is a newly discovered component of the stress response and normal developmental program of eukaryotic cells. The proposed studies with further our knowledge of this fundamental aspect of cellular biochemistry.