mediator of paramutation1 is required for establishment and maintenance of paramutation at multiple maize loci
mediator of paramutation1 is required for establishment and maintenance of paramutation at multiple maize loci
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DOI：
10.1105/tpc.12.11.2101
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发表时间：
2000-11-01
期刊：
影响因子：
11.6
通讯作者：
Chandler, VL
中科院分区：
文献类型：
--
作者：
Dorweiler, JE;Carey, CC;Chandler, VL
副突变是指一个等位基因与另一个等位基因杂合子时，其表达发生定向的、可遗传的改变。在这里，分离和表征的突变影响paramutation，调解paramutation 1 -1（mop 1 -1），进行了说明。实验表明，野生型基因Mop 1是建立和维持副突变体状态所必需的。mop 1 -1突变影响多个位点的副突变，但对不参与副突变的等位基因没有影响。该突变不会改变肌动蛋白和泛素转录物的数量，这表明mop 1基因不编码全局阻遏物。mop 1 -1纯合的玉米植株可能具有多效性发育缺陷，这表明mop 1 -1可能影响比已知的副突变体更多的基因。mop 1 -1突变不改变rDNA和着丝粒重复序列中DNA甲基化的程度。尽管这些基因座在其基因结构、与DNA甲基化的相关性和副突变状态的稳定性方面存在重大差异，但观察到mop 1影响多个基因座的副突变，这表明副突变背后有一个共同的机制。基于蛋白质的表观遗传模型的副突变进行了讨论。
Paramutation is the directed, heritable alteration of the expression of one allele when heterozygous with another allele. Here, the isolation and characterization of a mutation affecting paramutation, mediator of paramutation1-1 (mop1-1), are described. Experiments demonstrate that the wild-type gene Mop1 is required for establishment and maintenance of the paramutant state. The mop1-1 mutation affects paramutation at the multiple loci tested but has no effect on alleles that do not participate in paramutation. The mutation does not alter the amounts of actin and ubiquitin transcripts, which suggests that the mop1 gene does not encode a global repressor. Maize plants homozygous for mop1-1 can have pleiotropic developmental defects, suggesting that mop1-1 may affect more genes than just the known paramutant ones. The mop1-1 mutation does not alter the extent of DNA methylation in rDNA and centromeric repeats. The observation that mop1 affects paramutation at multiple loci, despite major differences between these loci in their gene structure, correlations with DNA methylation, and stability of the paramutant state, suggests that a common mechanism underlies paramutation. A protein-based epigenetic model for paramutation is discussed.