Tracking Proteins in Recombination Nodules During Synapsis

该研究计划是利用光和电子显微镜免疫定位的保守重组蛋白，更充分地整合基因重组的分子方面与早期重组结节（EN），晚期重组结节（LN）和联会复合体的细胞学结构。 番茄是本研究的最佳选择，原因有很多，包括其出色的细胞学，番茄EN和LN的广泛信息，以及已经有许多番茄重组蛋白的抗体。本研究的三个具体目标是：1）利用光学和电子显微镜确定整个突触中重组结节中重组蛋白的免疫标记模式。这方面的研究将包括详细的EM观察标记和未标记的EN，包括它们之间的关系，突触起始位点和突触叉，和LN。 2)验证突触形成过程中神经元在蛋白质组成和功能上存在差异的假设。 这可能与目前的证据有关，即一个子集的EN成为LN和/或有一个以上的遗传重组途径。 和3）检验在LN（交换）之间存在确定数量的EN（基因转换）的假设。 这一假说被认为是解释遗传干扰的一种可能机制。 这项研究将提供一个重要的一步，在我们的RN组件有关突触，交换，遗传干扰的理解。此外，这项工作将帮助我们评估减数分裂途径的保守方面，以及确定可能是特定于植物的功能。 更广泛地说，阐明番茄（一种作物）的这些特征可能有助于解决实际问题，例如改变重组率和/或在植物育种计划中帮助将所需的“野生”等位基因转移到驯化物种。 由于减数分裂重组是高度保守的，本研究的结果将普遍适用于其他具有经济重要性的植物，如玉米和水稻。 这项工作的一个重要内容将是培训和教育几名本科生以及一名研究生。

The research plan is to use light and electron microscopic immunolocalization of conserved recombination proteins to integrate more fully the molecular aspects of genetic recombination with the cytological structures of early recombination nodules (ENs), late recombination nodules (LNs) and synaptonemal complexes. Tomato is the optimum choice for this study for a number of reasons, including its excellent cytology, the extensive information available on tomato ENs and LNs, and the fact that antibodies are already available for a number of tomato recombination proteins. The three specific objectives for this research are: 1) To determine the pattern of immunolabeling of recombination proteins in recombination nodules throughout synapsis using both light and electron microscopy. This aspect of the research will include detailed EM observations of labeled and unlabeled ENs including their relationship to each other, to synaptic initiation sites and synaptic forks, and to LNs. 2) To test the hypothesis that ENs differ in protein composition and function during synapsis. This may be related to current evidence that a subset of ENs become LNs and/or that there is more than one pathway for genetic recombination. And 3) to test the hypothesis that there are a defined number of ENs (gene conversions) between LNs (crossovers). This hypothesis has been proposed as a possible mechanism to account for genetic interference. This research will provide an important step in our understanding of RN components in relation to synapsis, crossing over, and genetic interference. In addition, this work will help us evaluate conserved aspects of the meiotic pathway as well as identify features that may be specific to plants. More broadly, elucidating these features in tomato, a crop plant, may help with practical issues such as changing recombination rates and/or aiding transfer of desirable "wild" alleles to domesticated species in plant breeding programs. Because meiotic recombination is highly conserved, the results of this study will be generally applicable to other plants of economic importance, such as maize and rice. An important element of this work will be the training and education of several undergraduate students as well as a graduate student.