The Spatiotemporal Control of Zygotic Genome Activation
The Spatiotemporal Control of Zygotic Genome Activation
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DOI：
10.1016/j.isci.2019.06.013
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发表时间：
2019-06-28
期刊：
影响因子：
5.8
通讯作者：
Smith, James C.
中科院分区：
文献类型：
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作者：
Gentsch, George E.;Owens, Nick D. L.;Smith, James C.
合子基因组激活(ZGA)是胚胎发育中最早也是最重要的事件之一。在一些物种中，批量转录始于中期胚泡转变(MBT)，在一定数量的卵裂后，胚胎达到特定的核质比(N/C)，母体抑制因子变得足够稀薄，细胞周期减慢。在这里，我们通过分析RNA聚合酶II(RNAPII)的参与及其转录读出，在时间和空间上解析了青蛙ZGA。我们检测到在MBT之前RNAPII延长的数量和长度都逐渐增加，揭示了>；1000合子基因忽略了它们激活的N/C计时器，并且新转录基因的大小不一定受到细胞周期持续时间的限制。我们还发现，Wnt、Nodal和BMP信号共同产生了区域ZGA的大部分时空动力学，指导了正交体轴和比例胚层的形成。
One of the earliest and most significant events in embryonic development is zygotic genome activation (ZGA). In several species, bulk transcription begins at the midblastula transition (MBT) when, after a certain number of cleavages, the embryo attains a particular nuclear-to-cytoplasmic (N/C) ratio, maternal repressors become sufficiently diluted, and the cell cycle slows down. Here we resolve the frog ZGA in time and space by profiling RNA polymerase II (RNAPII) engagement and its transcriptional readout. We detect a gradual increase in both the quantity and the length of RNAPII elongation before the MBT, revealing that >1,000 zygotic genes disregard the N/C timer for their activation and that the sizes of newly transcribed genes are not necessarily constrained by cell cycle duration. We also find that Wnt, Nodal, and BMP signaling together generate most of the spatiotemporal dynamics of regional ZGA, directing the formation of orthogonal body axes and proportionate germ layers.