Regulation of Mu Activity in Maize

9603119自由转座子技术片段一个典型的玉米突变体(Mu)系携带大约100Mu转座子和大约5个称为MUDR的自主MU转座子。已经确定了承载一条MuDR的最小线路的特征。所有由转座、切除、去甲基化和抑制Mu诱导的等位基因诱导的表型都由该元件指定。MuDR-1的缺失分析将继续进行，以便将特定功能归因于MuDR DNA结构区域和编码蛋白A和B的结构域。将制备针对A的抗体，并利用已有的针对B的抗体，进行免疫定位和核蛋白共沉淀实验。Mu抑制的机制将用定量分析来研究，反向遗传学将被用来针对MuDR-1(P1)的特定区域的小片段缺失。观察到的Mu在发育和近亲交配后变得不那么活跃的现象将被调查，即使基因组中存在完整的MuDR元件，称为“显性负调控”。将使用Mu切除事件来研究启动子的多样性，该事件导致了一系列错误修复事件，影响了大约400bp的区域。通过有性杂交将一种单一的MuDR基因导入燕麦中，并对其在一种非本土牧草中的行为进行了分析。非技术摘要将研究一种原产于玉米Mu的转座元素。与玉米基因组中通常存在的许多主元件不同，只含有一个主元件的菌株将被用来研究该元件的结构和功能。将研究一种现象，即显性负调控，即使基因组中存在许多结构完整的元件，它也会导致Mu元件在发育期间和近亲交配后的活性丧失。该菌株及其后代的可获得性也使研究启动子序列变异的影响和转座子在转移到外源宿主时的行为成为可能。

9603119 Freeling Technical section A typical Mutator (Mu) line of maize carries about 100 Mu transposons and about five autonomous Mu transposons called MuDR. A minimal line that carries a single MuDR has been characterized. All phenotypes induced by transposition, excision, demethylation, and suppression of Mu-induced alleles, are specified by this element. Deletion analysis of MuDR-1 will be continued in order to ascribe specific functions to regions of MuDR DNA structure and domains of the encoded proteins A and B. Antibody to A will be prepared and with the already available antibody to B, immunolocalization and nuclear protein coprecipitation experiments will be done. The mechanism of Mu suppression will be studied using a quantitative assay, and reverse genetics will be used to target small deletions to particular regions of MuDR-1 (p1). The observed phenomenon whereby Mu becomes less active during development and following inbreeding even though intact MuDR elements exist in the genome called "dominant negative regulation", will be investigated. Promoter diversity will be studied using a Mu excision event which resulted in a series of mis-repair events affecting a region of about 400 bp. A single MuDR element has been introduced into oat via a sexual cross and its behavior in a non-native species of grass will be analyzed. Non-technical abstract A transposable element native to corn, Mu, will be studied. A strain which contains only one master element, in contrast to the many usually present in the corn genome, will be used to study the structure and the function of the element. A phenomenon, dominant negative regulation, which results in a cession of activity by the Mu element during development and following inbreeding even though many structurally intact elements are present in the genome, will be investigated. The availability of this strain and its progeny also makes it possible to study the effects of variation in promoter sequence and the behavior of the transposon when it is transferred to a foreign host.