SHORT INTEGUMENTS1/SUSPENSOR1/CARPEL FACTORY, a Dicer homolog, is a maternal effect gene required for embryo development in Arabidopsis
SHORT INTEGUMENTS1/SUSPENSOR1/CARPEL FACTORY, a Dicer homolog, is a maternal effect gene required for embryo development in Arabidopsis
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DOI：
10.1104/pp.003491
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发表时间：
2002-10-01
期刊：
影响因子：
7.4
通讯作者：
Ray, A
中科院分区：
文献类型：
--
作者：
Golden, TA;Schauer, SE;Ray, A
在动物发育中，母体细胞在控制早期胚胎发生中的重要性是众所周知的，但在植物中，母体细胞在胚胎发生中的确切作用尚不清楚。我们先前已经证明，拟南芥SIN1(Short INTEGUMENTS1)基因的母体活性对于胚胎模式的形成和活力是必不可少的，并且它的胚后活性是生殖发育过程中所必需的，包括开花时间控制和胚珠形态形成。在这里，我们报道了SIN1的克隆，并证明了它与对正常花形态发生至关重要的CAF(心皮工厂)基因和对胚胎发生至关重要的Sus1(SUSPENSOR1)基因的同源性。SIN1/Sus1/Caf与果蝇黑腹果蝇基因DICER序列相似，DICER基因编码双链RNA特异的多结构域核糖核酸酶，首次通过其在RNA沉默中的作用而被鉴定。通过加工小的RNA发夹，进而抑制靶mRNAs的翻译，Diller蛋白对于动物发育的时间控制是必不可少的。对野生型和SIN1突变蛋白的结构模拟表明，SIN1/Sus1/Caf的RNA解旋酶结构域具有重要的功能。在花分生组织、胚珠和早期胚胎中检测到该基因，这与突变的表型一致。SIN1/Sus1/Caf基因5‘端的3.3kb区域在胚胎中表现出不对称的亲本活性：只有当报告基因通过母系配子传递时，它才能在早期胚胎中实现转录激活。这些结果表明，母体SIN1/Sus1/CAF在拟南芥发育早期发挥作用，可能是通过转录后调节特定的mRNA分子。
The importance of maternal cells in controlling early embryogenesis is well understood in animal development, yet in plants the precise role of maternal cells in embryogenesis is unclear. We demonstrated previously that maternal activity of the SIN1 (SHORT INTEGUMENTS1) gene of Arabidopsis is essential for embryo pattern formation and viability, and that its postembryonic activity is required for several processes in reproductive development, including flowering time control and ovule morphogenesis. Here, we report the cloning of SIN1, and demonstrate its identity to the CAF (CARPEL FACTORY) gene important for normal flower morphogenesis and to the SUS1 (SUSPENSOR1) gene essential for embryogenesis. SIN1/SUS1/CAF has sequence similarity to the Drosophila melanogaster gene Dicer, which encodes a multidomain ribonuclease specific for double-stranded RNA, first identified by its role in RNA silencing. The Dicer protein is essential for temporal control of development in animals, through the processing of small RNA hairpins that in turn inhibit the translation of target mRNAs. Structural modeling of the wild-type and sin 1 mutant proteins indicates that the RNA helicase domain of SIN1/SUS1/CAF is important for function. The mRNA was detected in floral meristems, ovules, and early embryos, consistent with the mutant phenotypes. A 3.3-kb region 5' of the SIN1/SUS1/CAF gene shows asymmetric parent-of-origin activity in the embryo: It confers transcriptional activation of a reporter gene in early embryos only when transmitted through the maternal gamete. These results suggest that maternal SIN1/SUS1/CAF functions early in Arabidopsis development, presumably through posttranscriptional regulation of specific mRNA molecules.