Novel ribosomal genes from maize are differentiaily expressed in the zygotic and somatic cell cycles
Novel ribosomal genes from maize are differentiaily expressed in the zygotic and somatic cell cycles
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DOI：
10.1007/s004380050983
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发表时间：
1999-03-01
期刊：
影响因子：
--
通讯作者：
Kranz, E
中科院分区：
文献类型：
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作者：
Dresselhaus, T;Cordts, S;Kranz, E
我们已经从玉米未受精卵细胞和合子的文库中分离出代表50多种不同基因的cDNA，这些基因的表达在体外受精（IVF）后上调或下调。在分离的cDNA中，有七个编码可能参与翻译的蛋白质，两个编码可能参与DNA复制的蛋白质。后一种基因在受精时被强烈诱导。这表明合子基因激活（ZGA）-从母体到胚胎控制发育的转换-在高等植物受精后不久发生在合子中-比迄今为止研究的动物系统更早。对四种参与核糖体合成和翻译的核糖体蛋白（S21 A，S21 B，L39，P0）的新转录本进行了详细的分析。所有四个基因的表达与细胞分裂活性相关，并在体细胞周期的G1期强烈诱导。在第一个胚胎细胞周期中有一种不同的调控模式：相对大量的转录本储存在未受精的卵细胞中，在IVF后18小时，两个核糖体基因被诱导，而第三个基因被下调。这些结果表明，利用单细胞培养技术与新的分子方法相结合，有可能分离和研究许多基因表达的雌性配子和合子的高等植物。对四种核糖体蛋白基因的详细分析表明，合子细胞周期和体细胞周期受到差异调节。
We have isolated cDNAs representing more than 50 different genes from libraries of unfertilised egg cells and zygotes of maize, expression of which is up- or downregulated after in vitro fertilisation (IVF). Among the cDNAs isolated are seven which encode proteins that are probably involved in translation and two encoding proteins probably involved in DNA replication. The latter genes are strongly induced on fertilisation. This indicates that zygotic gene activation (ZGA)- the switch from maternal to embryonic control of development - occurs in the zygote shortly after fertilisation in higher plants - earlier than in animal systems so far investigated. Four novel transcripts for ribosomal proteins (S21A, S21B, L39, P0) involved in ribosome biosynthesis and translation were analysed in more detail. The expression of all four genes correlates with cell division activity and is strongly induced during the G1 phase of the somatic cell cycle. A different mode of regulation operates in the first embryonic cell cycle: relatively large amounts of transcript are stored in the unfertilised egg cells, and by 18 h after IVF, two ribosomal genes are induced while a third is downregulated. These results indicate that using the combination of single-cell culture techniques with novel molecular methods, it is possible to isolate and study numerous genes expressed in female gametes and zygotes of higher plants. The detailed analysis of the four ribosomal protein genes demonstrates that the zygotic and somatic cell cycles are differentially regulated.