Large tandem duplication associated with a Mu2 insertion in Zea mays B-Peru gene.
Large tandem duplication associated with a Mu2 insertion in Zea mays B-Peru gene.
复制标题
与玉米 B-秘鲁基因中 Mu2 插入相关的大串联重复。
DOI：
10.1007/bf00028876
复制
发表时间：
1994
影响因子：
5.1
通讯作者：
Chandler,VL
中科院分区：
文献类型：
--
作者：
Harris,LJ;Currie,K;Chandler,VL
玉米花色素苷生物合成途径的转录激活因子。B-Peru等位基因在种子的糊粉层中表达，导致该组织出现深紫色色素沉着。一个不稳定的突变体诱导的B-Perumutant等位基因，b-Perum 220，表现出弱的，可变的色素和高的衰老逆转率，而不是其他突变体插入的特征。对b-Perum 220相关区域的分析表明，在534 bp序列的一个拷贝中插入了一个Mu 2元件。该534 bp序列在B-Peru转录起始位点上游的祖先B-Peru等位基因中串联三重。除了Mu 2插入外，b-Perum 220等位基因还含有一个新形成的4.0kb的大串联重复，它包括B-Peru基因的启动子区和前三个外显子。Mu 2元素不位于任何复制断点。对11个独立的germ回复突变体的分子研究揭示了5种结构类型，包括4.0 kb串联重复部分或完全缺失、Mu 2元件部分或完全缺失或这些事件的组合发生的结构。我们假设大多数回复突变体是由重复区域之间的不平等重组引起的。基于这些结构分析，讨论了解释b-Perum 220中b基因表达降低的模型。
Theblocus ofZea maysencodes a transcriptional activator of the anthocyanin biosynthetic pathway. TheB-Peruallele is expressed in the aleurone layer of the seed, which results in dark purple pigmentation of this tissue. An unstableMutator-inducedB-Perumutant allele,b-Perum220, displays weak, variable pigment and a high germinal reversion rate not characteristic of otherMutatorinsertions. Characterization of relevant regions ofb-Perum220revealed aMu2element insertion in one copy of a 534 bp sequence. This 534 bp sequence is tandemly triplicated in the progenitorB-Peruallele, upstream of theB-Perutranscription start site. In addition to theMu2insertion, theb-Perum220allele contains a newly formed large tandem duplication of 4.0 kb, which includes the promoter region and the first three exons of theB-Perugene. TheMu2element does not reside at any of the duplication breakpoints. The molecular study of eleven independent germinal revertants revealed five structural classes including structures in which the 4.0 kb tandem duplication is partially or completely deleted, theMu2element is partially or completely deleted, or a combination of these events has occurred. We hypothesize that most of the revertants arose by unequal recombination between the duplicated regions. Based on these structural analyses, models are discussed to explain the reducedbgene expression inb-Perum220.