Members of the RKD transcription factor family induce an egg cell-like gene expression program
Members of the RKD transcription factor family induce an egg cell-like gene expression program
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DOI：
10.1111/j.1365-313x.2011.04592.x
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发表时间：
2011-07-01
期刊：
影响因子：
7.2
通讯作者：
Baeumlein, Helmut
中科院分区：
文献类型：
--
作者：
Koszegi, David;Johnston, Amal J.;Baeumlein, Helmut
与动物相反，高等植物的生命周期在产生配子（配子体）和产生孢子（孢子体）的世代之间交替。被子植物的雌配子体由四种不同的细胞类型组成，包括两种配子，即卵和中央细胞，它们分别产生胚和胚乳。基于小麦（Triticum aestivum L.）消减杂交和虚拟消减杂交相结合的方法，我们已经分离了一类在动物基因组中未发现的转录因子，RKD（含RWP-RK结构域）因子，其共享高度保守的RWP-RK结构域。单细胞RT-PCR结果表明，TaRKD 1和TaRKD 2基因在小麦卵细胞中优先表达。拟南芥基因组包含五个RKD基因，其中至少两个AtRKD 1和AtRKD 2在拟南芥卵细胞中优先表达。AtRKD 1和AtRKD 2基因的异位表达诱导细胞增殖和卵细胞标志物的表达。对RKD诱导的增殖细胞的分析显示基因表达向卵细胞样转录组转移。所选RKD诱导的基因的启动子被证明是主要活跃在卵细胞中，可以被激活的RKD在瞬时原生质体表达测定。数据显示，卵细胞特异性RKD因子控制转录程序，这是植物卵细胞的特征。
In contrast to animals, the life cycle of higher plants alternates between a gamete-producing (gametophyte) and a spore-producing (sporophyte) generation. The female gametophyte of angiosperms consists of four distinct cell types, including two gametes, the egg and the central cell, which give rise to embryo and endosperm, respectively. Based on a combined subtractive hybridization and virtual subtraction approach in wheat (Triticum aestivum L.), we have isolated a class of transcription factors not found in animal genomes, the RKD (RWP-RK domain-containing) factors, which share a highly conserved RWP-RK domain. Single-cell RT-PCR revealed that the genes TaRKD1 and TaRKD2 are preferentially expressed in the egg cell of wheat. The Arabidopsis genome contains five RKD genes, at least two of them, AtRKD1 and AtRKD2, are preferentially expressed in the egg cell of Arabidopsis. Ectopic expression of the AtRKD1 and AtRKD2 genes induces cell proliferation and the expression of an egg cell marker. Analyses of RKD-induced proliferating cells exhibit a shift of gene expression towards an egg cell-like transcriptome. Promoters of selected RKD-induced genes were shown to be predominantly active in the egg cell and can be activated by RKD in a transient protoplast expression assay. The data show that egg cell-specific RKD factors control a transcriptional program, which is characteristic for plant egg cells.