n nnnWhether deposited maternal products are important during earlyseed development in flowering plants remains controversial.Here, we show that RNA interference–mediated downregulationof transcription is deleterious to endosperm development butdoes not block zygotic divisions. Furthermore, we show thatRNA POLYMERASE II is less active in the embryo than in the endosperm.This dimorphic pattern is established late during female gametogenesisand is inherited by the two products of fertilization. Thisjuxtaposition of distinct transcriptional activities correlateswith differential patterns of histone H3 lysine 9 dimethylation,LIKE HETEROCHROMATIN PROTEIN1 localization, and Histone H2Bturnover in the egg cell versus the central cell. Thus, distinctepigenetic and transcriptional patterns in the embryo and endospermare already established in their gametic progenitors. We furtherdemonstrate that the non-CG DNA methyltransferase CHROMOMETHYLASE3(CMT3) and DEMETER-LIKE DNA glycosylases are required for thecorrect distribution of H3K9 dimethylation in the egg and centralcells, respectively, and that plants defective for CMT3 activityshow abnormal embryo development. Our results provide evidencethat cell-specific mechanisms lead to the differentiation ofepigenetically distinct female gametes in Arabidopsis thaliana.They also suggest that the establishment of a quiescent statein the zygote may play a role in the reprogramming of the youngplant embryo.展开▼
机译：ABSTRACTn n
n TOP n <字体颜色= 464c53>抽象 n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n n nnn在 早期种子期间母体沉积物是否重要 在这里，我们显示RNA干扰介导的转录下调 对胚乳发育有害，但 不会阻断合子师。此外，我们显示 RNA POLYMERASE II在胚胎中的活性低于胚乳。 这种双态模式是在雌性配子发生后期建立的。是受精的两种产物。 的不同转录活性的并置将 与组蛋白H3赖氨酸9的二甲基化， 像异染色质蛋白1的定位和组蛋白H2B / SUP>卵细胞与中心细胞的周转率。因此，胚胎和胚乳 的配子祖细胞中已经建立了明显的 表生和转录方式。我们进一步 证明了非CG DNA甲基转移酶CHROMOMETHYLASE3 （CMT3）和类似DEMETER的DNA糖基化酶对于H3K9甲基化的 正确分布分别在卵细胞和中央 细胞中存在缺陷，并且CMT3活性 有缺陷的植物显示出异常的胚胎发育。我们的结果提供了证据 ，即细胞特异性机制导致拟南芥中表观遗传上不同的雌配子的分化。 他们还建议在合子中建立静态 可能在年轻的 植物胚胎的重编程中起作用。展开▼
