HUA1 AND HUA2 IN ARABIDOPSIS FLOWER DEVELOPMENT

我们对多细胞生物发展中的一个基本问题感兴趣，即，一些未分化的细胞是如何获得它们的身份并形成独特的模式的。我们选择在拟南芥花发育的背景下来解决这个问题。特别是，我们正在研究前体细胞如何承担他们的身份和发展成为雄蕊和心皮，男性和女性的生殖生物的花。很长一段时间，AG，MADS结构域转录因子，是唯一已知的蛋白质参与这一发育过程。目前尚不清楚单个转录因子如何导致复杂器官如雄蕊和心皮的最终形成。我们的长期目标是充分剖析AG通路，以了解这一复杂的发育过程。AG途径的两个新成员，HUA1和HUA2，从我们的增强子筛选中分离出使用弱ag等位基因。HUA2是通过图位克隆策略克隆的。 它编码AG的一个假定的转录因子和转录共激活因子。HUA1的克隆已经取得了重大进展。本研究旨在揭示HUA1和HUA2在拟南芥花发育中的分子机制。首先，将在蛋白质水平上研究HUA2。将确定植物内的HUA2蛋白定位模式。实验将进行研究AG和HUA2之间的物理相互作用，这在我们的初步研究中观察到。我们的基因，其产品与HUA2相互作用将被分离与酵母双杂交筛选。其次，HUA1将被克隆并在分子水平上进行研究。将确定其在植物内的RNA定位模式。将研究HUA1、HUA2和AG蛋白之间的潜在相互作用。第三，HUA1和HUA2的其他突变等位基因将被分离，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。T-DNA插入系的分子筛选和Hua 1 Hua 2增强子筛选的组合将用于该目的。详细了解拟南芥同源异型途径将是一个宝贵的除了我们的知识发展过程中的一般。植物和动物的同源异型途径可以与衍生的进化原理相比较。此外，在像拟南芥这样的简单生物体中研究植物发育可能会加快我们对人类等更复杂生物体的理解。鉴于HUA2与C.线虫、果蝇、小鼠和人类的同源异型途径中，一些植物基因的分子功能在动物中是保守的，这并不奇怪。

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.