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Self recognition and signaling in plant reproduction

植物繁殖中的自我识别和信号传导

基本信息

批准号：
6915691
负责人：
JUNE B NASRALLAH
金额：
$ 30.76万
依托单位：
CORNELL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-05-01 至 2007-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The goal of the proposed research is to understand how cell-cell recognition signals the arrest of a critical developmental pathway in the reproductive phase of the plant's life cycle. Our experimental system is the self-incompatibility response of crucifers, which is an ultra-specific mating barrier that prevents self-fertilization by arresting the development of genetically related "self" pollen grains. The recognition of self in this system is based on the activity of highly diverged alleles of a transmembrane receptor protein kinase and its defensin-like peptide ligand, which are the female and male determinants of specificity, respectively. We plan to extend research during the current funding period, which identified and described several characteristics of the ligand, and demonstrated that specificity in the self-incompatibility response is based on allele-specific receptor-ligand interactions. We propose to perform structure-activity relationship studies of receptor and ligand with the goal of mapping domains that determine specificity in their interaction and in activation of the pollen-inhibitory signal transduction pathway. We also plan to investigate the self-incompatibility signal transduction pathway using molecular genetic and proteomics approaches. The intra-specific divergence of these receptor-ligand pairs exceeds the inter-specific divergence typical of many reproductive proteins, such as mammalian proteins that function in species-specific sperm-egg interaction. Also like other self/nonself recognition molecules, the SI proteins are subject to diversifying selection and must co-evolve to maintain their specific interaction. Because the two interacting partners in SI recognition are known, and a large number of natural receptor-ligand variants are available for study, the SI system of crucifers is ideally suited for exploring the structural basis of specific receptor-ligand interactions and for gaining insight into the co-evolution of gene functions that typically underlies recognition phenomena.

描述（由申请人提供）：拟议研究的目标是了解细胞-细胞识别如何发出信号，阻止植物生命周期生殖阶段的关键发育途径。我们的实验系统是十字花科植物的自交不亲和反应，这是一种超特异性的交配障碍，通过阻止遗传相关的“自我”花粉粒的发育来防止自花受精。在这个系统中，自我的识别是基于跨膜受体蛋白激酶及其防御素样肽配体的高度分化的等位基因的活性，它们分别是特异性的女性和男性决定因素。我们计划在目前的资助期内扩展研究，该研究确定并描述了配体的几个特征，并证明了自交不亲和反应的特异性是基于等位基因特异性受体-配体相互作用。我们建议进行构效关系的受体和配体的映射域，确定其相互作用的特异性和激活的花粉抑制信号转导通路的目标研究。我们还计划利用分子遗传学和蛋白质组学方法研究自交不亲和性的信号转导途径。这些受体-配体对的种内差异超过了许多生殖蛋白的种间差异，例如在物种特异性精子-卵子相互作用中起作用的哺乳动物蛋白。也像其他自我/非自我识别分子一样，SI蛋白受到多样化的选择，必须共同进化以维持它们的特异性相互作用。由于SI识别中的两个相互作用的合作伙伴是已知的，并且大量的天然受体-配体变体可用于研究，十字花科植物的SI系统非常适合于探索特定受体-配体相互作用的结构基础，并深入了解通常作为识别现象基础的基因功能的共同进化。