Functional Genomics of the Biotin Metabolic Network of Arabidopsis

智力优势：生物素是一种必需分子，其主要功能被认为是参与多种代谢过程的酶所需要的催化辅助因子。最近的研究表明，生物素也是一种调控分子，在控制基因表达的转录和转录后机制中发挥关键作用。本研究将以拟南芥为模型，识别和表征真核生物生物素代谢网络相关基因的生化和生理功能。植物非常适合进行这些研究，因为它们和一些微生物是能够从头合成这种分子的主要生物；所有其他生物都必须从它们的饮食或环境中获取这种分子。该项目将描述生物素代谢网络的各个方面，这些方面是所研究的生物体所特有的，即拟南芥，作为一种模式植物。具体来说：1)发育和环境因素如何调节生物素的生物合成；这些研究将利用研究人员最近发现的两个生物素生物合成基因BIO1和BIO2；2)植物特异性含生物素蛋白的生化生理功能。它们是甲基巴豆酰辅酶a羧化酶（由基因At1g03090和At4g34030编码）、种子特异性生物素蛋白（由基因At2g42560编码）和三个生物素载体样蛋白（由基因At1g52670、At3g15690、At3g56130编码）；3)生物素在转录和转录后水平调控基因表达的机制。更广泛的影响：该项目将成为教育和培训本科、研究生和研究生水平的新一代科学家骨干的工具。将提供实验室研究经验，让年轻科学家接触功能基因组学和生物技术的多学科基础研究。该研究将定义围绕生物素的催化和调节功能构建的复杂代谢网络的组织。这一成就将为研究如此复杂的网络是如何被调控提供新的见解。目标是建立一个例子，说明如何将新陈代谢视为一个复杂的综合网络，而不是一组线性途径的经典教科书模型。这种代谢观的发展只有在基因组被完全测序的生物体的背景下才有可能。为了全面理解代谢过程是如何被发育和环境因素相互调节的，需要对代谢有这样的理解。

Intellectual merit: Biotin is an essential molecule, whose primary function has been ascribed as a catalytic cofactor required by enzymes involved in diverse metabolic processes. Recent studies indicate that biotin is also a regulatory molecule that appears to play critical roles in controlling transcriptional and post-transcriptional mechanisms in gene expression. This research will identify and characterize the biochemical and physiological functions of genes associated with the biotin metabolic network of eukaryotic organisms, using Arabidopsis as a model. Plants are ideally suited for these studies as they, along with some microbes, are the primary organisms that can synthesize this molecule de novo; all other organisms must acquire this molecule from their diets or from the environment. This project will characterize aspects of the biotin metabolic network that are unique to the organism under study, namely Arabidopsis, as a model plant. Specifically: 1) how do developmental and environmental cues regulate biotin biosynthesis; these studies will take advantage of the two biotin biosynthetic genes that have recently been identified by the investigators, BIO1 and BIO2; and 2) what is the biochemical and physiological function of plant-specific biotin-containing proteins. These are methylcrotonyl-CoA carboxylase (encoded by genes At1g03090 and At4g34030), the seed-specific biotin protein (encoded by gene At2g42560), and three biotin carrier-like proteins (encoded by genes At1g52670, At3g15690, At3g56130); and 3) what are the mechanisms by which biotin regulates gene expression at both the transcriptional and post-transcriptional level.Broader impact: The project will be a vehicle for the education and training of a new cadre of scientists at the undergraduate, graduate and post-graduate levels. In-lab research experiences will be provided for exposing young scientists to multidisciplinary basic research in functional genomics and biotechnology. The research will define the organization of a complex metabolic network that is structured around the catalytic and regulatory functions of biotin. This achievement will provide novel insights into how such complex networks are regulated. The goal is to develop an example of how to view metabolism as a complex integrated network rather than the classical textbook model of a set of linear pathways. The development of this view of metabolism is possible only in the context of an organism whose genome is completely sequenced. Such an understanding of metabolism is required in order to comprehensively understand how metabolic processes are interactively regulated by developmental and environmental cues.