Maintenance of DNA methylation during the Arabidopsis life cycle is essential for parental imprinting
Maintenance of DNA methylation during the Arabidopsis life cycle is essential for parental imprinting
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DOI：
10.1105/tpc.106.041178
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发表时间：
2006-06-01
期刊：
影响因子：
11.6
通讯作者：
Berger, Frederic
中科院分区：
文献类型：
--
作者：
Jullien, Pauline E.;Kinoshita, Tetsu;Berger, Frederic
印记基因主要由其父本或母本等位基因表达。迄今为止，所有在植物中鉴定的印记基因都在胚乳中表达。在拟南芥中，母体印记已被清楚地证明为Polycomb组基因MEDEA（MEA）和FWA。FWA上游的直接重复序列经历DNA甲基化。然而，目前还不清楚在何种程度上类似的顺式作用元件可能是一个保守的分子机制控制的母系印记基因的一部分。在这项工作中，我们表明Polycomb组基因FIS2（FIS2）是印迹的。FIS2印迹的维持依赖于DNA甲基化，而DNA甲基化的丧失不影响MEA印迹。DNA甲基化靶向FIS2上游的一个小区域，不同于与FWA相关的DNA甲基化的靶点。我们表明，FWA和FIS2印迹需要在整个植物生活周期，包括雄配子发生和胚乳发育的DNA甲基化的维护。因此，我们的数据表明，父母在植物基因组印记依赖于不同的顺式元件和机制依赖或独立于DNA甲基化。我们建议，印记进化的限制下，植物繁殖的进化，而不是通过选择一个特定的分子机制。
Imprinted genes are expressed predominantly from either their paternal or their maternal allele. To date, all imprinted genes identified in plants are expressed in the endosperm. In Arabidopsis thaliana, maternal imprinting has been clearly demonstrated for the Polycomb group gene MEDEA ( MEA) and for FWA. Direct repeats upstream of FWA are subject to DNA methylation. However, it is still not clear to what extent similar cis-acting elements may be part of a conserved molecular mechanism controlling maternally imprinted genes. In this work, we show that the Polycomb group gene FERTILIZATION-INDEPENDENT SEED2 (FIS2) is imprinted. Maintenance of FIS2 imprinting depends on DNA methylation, whereas loss of DNA methylation does not affect MEA imprinting. DNA methylation targets a small region upstream of FIS2 distinct from the target of DNA methylation associated with FWA. We show that FWA and FIS2 imprinting requires the maintenance of DNA methylation throughout the plant life cycle, including male gametogenesis and endosperm development. Our data thus demonstrate that parental genomic imprinting in plants depends on diverse cis-elements and mechanisms dependent or independent of DNA methylation. We propose that imprinting has evolved under constraints linked to the evolution of plant reproduction and not by the selection of a specific molecular mechanism.