HUA1 AND HUA2 IN ARABIDOPSIS FLOWER DEVELOPMENT

HUA1 和 HUA2 在拟南芥花发育中的作用

• 批准号: 6520217
• 负责人: Xuemei Chen
• 金额: $ 22.91万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6520217
• 关键词: Arabidopsis; DNA binding protein; alleles; developmental genetics; gene expression; gene interaction; genetic mapping; histogenesis; molecular cloning; plant genetics; plant growth /development; plant morphology; polymerase chain reaction; protein protein interaction; yeast two hybrid system

We are interested in a fundamental issue in the development of multicellular organisms, i.e., how a few undifferentiated cells assume their identities and form distinct patterns. We have chosen to address this issue in the context of Arabidopsis flow development. In particular, we are studying how precursor cells assume their identifies and develop into stamens and carpels, the male and female reproductive organisms of the flower. For a long time, AG, a MADS domain transcription factor, was the only known protein involved in this developmental process. It is not clear how a single transcription factor leads to the eventual formation of complex organs such as stamens and carpels. It is our long-term goal to fully dissect the AG pathway in order to understand this complex developmental process. Two new members of the AG pathway, HUA1 and HUA2, were isolated from our enhancer screen using a weak ag allele. HUA2 was cloned with a map-base strategy. It codes for a putative transcription factor and transcriptional co-activator of AG. Significant progress has been made towards the cloning of HUA1. This proposal is aimed at uncovering the molecular mechanisms underlying the functions of HUA1 and HUA2 in Arabidopsis flower development. First, HUA2 will be studied at the protein level. HUA2 protein localization pattern within the plant will be determined. Experiments will be performed to study the physical interaction between AG and HUA2, which was observed in our preliminary studies. Our genes whose products interact with HUA2 will be isolated with a yeast two-hybrid screen. Second, HUA1 will be cloned and studied at the molecular level. Its RNA localization patterns within the plant will be determined. Potential interactions among HUA1, HUA2 and AG proteins will be investigated. Third, additional mutant alleles of HUA1 and HUA2 will be isolated, especially severe loss-of-function mutations, which will help solve some pending issues regarding the functions of HUA1 and HUA2 in the AG pathway. A combination of a molecular screen of T-DNA insertional lines and a Hua1 Hua2 enhancer screen will be employed for this purpose. A detailed understanding of a homeotic pathway in Arabidopsis will be an invaluable addition to our knowledge of developmental process in general. Plant and animal homeotic pathways can be compared to derived evolutionary principles. In addition, studying plant development in a simple organism like Arabidopsis will likely expedite our understanding of more complicated organisms such as humans. In light of the fact that HUA2 shares common motifs with genes in C. elegans, Drosophila, mice and humans, it will not be surprising that the molecular functions of some plant genes in homeotic pathways are conserved in animals.

我们感兴趣的是多细胞生物体发展中的一个基本问题，即少数未分化的细胞如何承担它们的身份并形成不同的模式。我们选择在拟南芥流动发展的背景下解决这个问题。特别是，我们正在研究前体细胞如何识别并发育成雄蕊和心皮，即花的雄性和雌性生殖有机体。长期以来，MADS结构域转录因子AG是唯一已知的参与这一发育过程的蛋白质。目前尚不清楚单个转录因子如何最终导致雄蕊和心皮等复杂器官的形成。我们的长期目标是全面剖析AG途径，以了解这一复杂的发育过程。从我们的增强子筛选中分离到两个AG途径的新成员，HUA1和HUA2，使用的是弱的AG等位基因。采用基于图库的策略克隆了HUA2。它编码一个可能的转录因子和AG的转录辅助激活因子。在克隆HUA1方面取得了重大进展。本研究旨在揭示HUA1和HUA2在拟南芥花发育中作用的分子机制。首先，将从蛋白质水平对HUA2进行研究。将确定HUA2蛋白在植物中的定位模式。我们将进行实验来研究AG和HUA2之间的物理相互作用，这是在我们的初步研究中观察到的。我们的产物与HUA2相互作用的基因将用酵母双杂交筛选来分离。其次，将从分子水平对HUA1进行克隆和研究。它在植物中的RNA定位模式将被确定。将研究HUA1、HUA2和AG蛋白之间的潜在相互作用。第三，将分离更多的HUA1和HUA2突变等位基因，特别是严重的功能丧失突变，这将有助于解决关于HUA1和HUA2在AG途径中的功能的一些悬而未决的问题。为此，将采用T-DNA插入系的分子筛选和HUA1 HUA2增强子筛选的组合。对拟南芥中同源异型途径的详细了解将是对我们一般发育过程知识的宝贵补充。植物和动物的同源同源途径可以与衍生的进化原理相比较。此外，研究拟南芥等简单生物体中的植物发育可能会加速我们对人类等更复杂生物体的理解。鉴于HUA2与线虫、果蝇、小鼠和人类的基因具有共同的基序，因此一些植物基因在同源异型途径中的分子功能在动物中保守也就不足为奇了。