THE DROSOPHILA CELLULARIZATION GENE NULLO PRODUCES A BLASTODERM-SPECIFIC TRANSCRIPT WHOSE LEVELS RESPOND TO THE NUCLEOCYTOPLASMIC RATIO
THE DROSOPHILA CELLULARIZATION GENE NULLO PRODUCES A BLASTODERM-SPECIFIC TRANSCRIPT WHOSE LEVELS RESPOND TO THE NUCLEOCYTOPLASMIC RATIO
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DOI：
10.1101/gad.6.7.1255
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发表时间：
1992-07-01
影响因子：
10.5
通讯作者：
WIESCHAUS, E
中科院分区：
文献类型：
--
作者：
ROSE, LS;WIESCHAUS, E
果蝇胚胎的初始发育特点是快速的核有丝分裂，无胞质分裂。经过 13 次这样的有丝分裂后，就会发生称为细胞化的协调细胞分裂过程，在此期间细胞膜同时包围细胞中的每个细胞核。细胞化需要在胚胎皮质中建立肌动蛋白和肌球蛋白丝的六边形网络；细丝位于内陷膜沟的细胞质面上。 nullo 基因的合子表达对于维持完整的肌动蛋白-肌球蛋白网络至关重要。我们克隆了 nullo 基因并展示了其序列以及野生型和突变体胚胎中 nullo 转录物水平的表征。 nullo 基因编码预测的 213 个氨基酸的蛋白质，其中很大一部分是碱性的。 nullo 转录物首先在核细胞周期 11 时被检测到，在周期 13 结束时达到峰值，并随着细胞化开始而迅速消失。该基因似乎在生物体生命中的任何其他时间都不表达。零转录本的正常积累不需要其他合子细胞化基因的基因活性。然而，第 14 周期期间无效 RNA 水平的调节与核质比率相关，这也控制着细胞化之前快速、同步有丝分裂的停止。
The initial development of the Drosophila embryo is characterized by rapid nuclear mitosis without cytokinesis. After 13 such mitoses, a coordinated cell division process called cellularization occurs, during which membranes simultaneously enclose each nucleus in a cell. Cellularization requires the establishment of a hexagonal network of actin and myosin filaments in the cortex of the embryo; the filaments are located on the cytoplasmic face of the invaginating membrane furrows. Zygotic expression of the nullo gene is essential for the maintenance of an intact actin-myosin network. We have cloned the nullo gene and present its sequence as well as a characterization of nullo transcript levels in wild-type and mutant embryos. The nullo gene encodes a predicted protein of 213 amino acids, a large proportion of which is basic. nullo transcripts are first detectable at nuclear cell cycle 11, peak in accumulation at the end of cycle 13, and disappear rapidly as cellularization begins. The gene does not appear to be expressed at any other time in the life of the organism. The normal accumulation of nullo transcripts does not require gene activity of other zygotic cellularization genes. The regulation of nullo RNA levels during cycle 14, however, is coupled to the nucleocytoplasmic ratio, which also controls the cessation of rapid, synchronous mitosis just before cellularization.