Lauria Massimiliano, Rupe Mary, Guo Mei, Kranz Erhard, Pirona Raul, Viotti Angelo, Lund Gertrud
Plant Biochemistry Laboratory, Department of Plant Biology, Royal Veterinary and Agricultural University, DK-1871 Frederiksberg C, Denmark.
Plant Cell. 2004 Feb;16(2):510-22. doi: 10.1105/tpc.017780. Epub 2004 Jan 16.
A PCR-based genomic scan has been undertaken to estimate the extent and ratio of maternally versus paternally methylated DNA regions in endosperm, embryo, and leaf of Zea mays (maize). Analysis of several inbred lines and their reciprocal crosses identified a large number of conserved, differentially methylated DNA regions (DMRs) that were specific to the endosperm. DMRs were hypomethylated at specific methylation-sensitive restriction sites upon maternal transmission, whereas upon paternal transmission, the methylation levels were similar to those observed in embryo and leaf. Maternal hypomethylation was extensive and offers a likely explanation for the 13% reduction in methyl-cytosine content of the endosperm compared with leaf tissue. DMRs showed identity to expressed genic regions, were observed early after fertilization, and maintained at a later stage of endosperm development. The implications of extensive maternal hypomethylation with respect to endosperm development and epigenetic reprogramming will be discussed.
已开展基于聚合酶链反应（PCR）的基因组扫描，以估计玉米胚乳、胚和叶片中母本与父本甲基化DNA区域的范围及比例。对多个自交系及其正反交组合进行分析，鉴定出大量保守的、差异甲基化DNA区域（DMR），这些区域是胚乳特有的。在母本传递时，DMR在特定的甲基化敏感限制位点处发生低甲基化，而在父本传递时，甲基化水平与在胚和叶片中观察到的相似。母本低甲基化现象广泛存在，这可能是胚乳中甲基胞嘧啶含量相较于叶片组织减少13%的原因。DMR与表达的基因区域具有一致性，在受精后早期即可观察到，并在胚乳发育后期得以维持。本文将讨论广泛的母本低甲基化对胚乳发育和表观遗传重编程的影响。
