Delayed activation of the paternal genome during seed development
Delayed activation of the paternal genome during seed development
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DOI：
10.1038/35003595
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发表时间：
2000-03-02
期刊：
影响因子：
64.8
通讯作者：
Grossniklaus, U
中科院分区：
文献类型：
--
作者：
Vielle-Calzada, JP;Baskar, R;Grossniklaus, U
在开花植物的种子发育过程中，关于母系向合子过渡的时间知之甚少。由于植物胚胎可以由体细胞或小孢子发育(1)，母体的贡献在早期胚胎发生中并不重要(2)。拟南芥中的早期胚胎致死性突变，包括影响第一次合子分裂的emb30/ gnm(3,4)，使人们认为母体和父亲的基因组在受精后立即活跃。在这里，我们发现我们测试的20个位点的父系遗传等位基因在拟南芥种子发育早期没有表达。对于在后期表达的基因，父亲遗传的等位基因在受精后三到四天变得活跃。我们测试的基因参与了不同的过程，分布在整个基因组中，这表明，如果不是全部的话，大部分父系基因组可能在最初是沉默的。我们的发现得到了遗传学研究的证实，表明emb30/ gnm除了具有合子致死率外，还具有母系效应表型，即父系可拯救表型。因此，与以往的解释相反，早期胚胎和胚乳的发育主要受母体的控制。
Little is known about the timing of the maternal-to-zygotic transition during seed development in flowering plants. Because plant embryos can develop from somatic cells or microspores(1), maternal contributions are not considered to be crucial in early embryogensis(2). Early-acting embryo-lethal mutants in Arabidopsis, including emb30/gnom which affects the first zygotic division(3,4) have fuelled the perception that both maternal and paternal genomes are active immediately after fertilization. Here we show that none of the paternally inherited alleles of 20 loci that we tested is expressed during early seed development in Arabidopsis. For genes that are expressed at later stages, the paternally inherited allele becomes active three to four days after fertilization. The genes that we tested are involved in various processes and distributed throughout the genome, indicating that most, if not all, of the paternal genome may be initially silenced. Our findings are corroborated by genetic studies showing that emb30/gnom has a maternal-effect phenotype that is paternally rescuable in addition to its zygotic lethality. Thus, contrary to previous interpretations, early embryo and endosperm development are mainly under maternal control.