MudrB Function in Maize and Origin within the Grasses

MudrB 在玉米中的功能和草丛中的起源

• 批准号: 0112346
• 负责人: Michael Freeling
• 金额: $ 37.08万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0112346&HistoricalAwards=false
• 关键词: MudrB; Function; Maize; Origin; within

The Mutator system is a highly mutagenic family of transposable elements in maize. Mutator transposition is regulated by the MuDR class of transposons. MuDR elements encode two genes: mudrA and mudrB. The mudrA gene is the putative transposase. Although known to be a necessary component of Mu activity, the biochemical function of the mudrB gene is not known. The primary objective of this research is to elucidate the evolution and function of this gene. The mudrA gene is much more widely distributed among grasses than mudrB. Based on this, and the absence of mudrB in many apparently functional MuDR-like elements, it is hypothesized that mudrB was captured by MuDR at some point during the evolution of this transposon. To test this hypothesis, several grasses related to maize will be surveyed for the presence and composition of mudrB sequences. To investigate the function of mudrB in maize, existing derivatives that express only mudrA or only mudrB will be exploited. Experiments in which these two deletion derivatives will be combined genetically will test the hypothesis that the two can compliment each other. In addition, the derivative that lacks mudrB will be crossed to mutations that affect Mutator activity. In order to determine if mudrB can contribute to high levels of MuDR transposition in a species that lacks this gene, rice will be transformed with constitutively and inducibly expressed mudrB. Proteomic analysis of proteins binding Mu element TIRs will be employed to identify proteins involved in regulating Mu element transposition in the presence and absence of mudrA or mudrB and in the presence of mutations that affect Mutator activity. Proteomic analysis of binding of Mu termini from these mutations will also serve to identify other proteins that operate in the same pathway as the mutations that affect activity.

Mutator系统是玉米转座因子的高诱变家族。突变子的转座是由MuDR类转座子调控的。MuDR元件编码两个基因：mudrA和mudrB。mudrA基因是假定的转座酶。虽然已知mudrB基因是Mu活性的必要组成部分，但其生化功能尚不清楚。本研究的主要目的是阐明该基因的进化和功能。mudrA基因在禾本科植物中的分布要比mudrB广泛得多。基于这一点，以及在许多明显具有功能的MuDR样元件中缺少mudrB，我们假设mudrB是在该转座子进化的某个阶段被MuDR捕获的。为了验证这一假设，将对几种与玉米有关的草进行调查，以确定mudrB序列的存在和组成。为了研究mudrB在玉米中的功能，将利用现有的仅表达mudrA或仅表达mudrB的衍生物。将这两种缺失衍生物结合在一起的实验将检验两者可以互补的假设。此外，缺乏mudrB的衍生物将被交叉到影响Mutator活性的突变上。为了确定mudrB是否会在缺乏该基因的物种中导致高水平的MuDR转位，水稻将被组成型和诱导表达的mudrB转化。结合Mu元件TIRs的蛋白质组学分析将用于鉴定在存在或不存在mudrA或mudrB以及存在影响Mutator活性的突变时参与调节Mu元件转位的蛋白质。对这些突变的Mu末端结合的蛋白质组学分析也将有助于识别与影响活性的突变在相同途径中运作的其他蛋白质。