Parallels and contrasts between the cnidarian and bilaterian maternal-to-zygotic transition are revealed in Hydractinia embryos.
Parallels and contrasts between the cnidarian and bilaterian maternal-to-zygotic transition are revealed in Hydractinia embryos.
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刺胞动物和两侧对称动物的母体向合子转变之间的相似性和对比在水螅胚胎中得到揭示。
DOI：
10.1101/2023.05.09.540083
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Lee,MilerT
中科院分区：
文献类型：
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作者：
Ayers,TaylorN;Nicotra,MatthewL;Lee,MilerT
胚胎发生需要早期协调的基因调控活动，以确定随后发育的轨迹，这一时期被称为母体到受精卵的转变(MZT)。MZT包括胚胎基因组的转录激活和卵子遗传的母体mRNA的转录后调节。对动物MZT的研究几乎完全集中在双边动物上，其中包括所有经典的模型，如苍蝇、蠕虫、海胆和脊椎动物，因此限制了我们理解所有动物中统一MZT的基因调控范例的能力。在这里，我们阐明了一种非双侧类的MZT，即CnidarianHydractinia symbiolongicarpus。使用并行的Poly(A)选择和非Poly(A)依赖的RNA-seq方法，我们发现Hydractinia MZT由类似于许多双边的调控活动组成，包括母体贡献的mRNA的细胞质再烯化，延迟的基因组激活，以及母体mRNA的死烯基化和降解的不同阶段，这可能取决于母体和合子编码的清除因子，包括microRNAs。但我们也观察到组蛋白基因的大量上调和预测的H4K20甲基转移酶的扩大，到目前为止，这些方面是Hydractinia MZT特有的，可能是早期胚胎染色质调节的新模式的基础。因此，在双侧和非双侧胚胎中，MZT都有类似的分类群特定阐述的调控策略，为了解祖先动物可能如何发生必要的发育转变提供了洞察。
Embryogenesis requires coordinated gene regulatory activities early on that establish the trajectory of subsequent development, during a period called the maternal-to-zygotic transition (MZT). The MZT comprises transcriptional activation of the embryonic genome and post-transcriptional regulation of egg-inherited maternal mRNA. Investigation into the MZT in animals has focused almost exclusively on bilaterians, which include all classical models such as flies, worms, sea urchin, and vertebrates, thus limiting our capacity to understand the gene regulatory paradigms uniting the MZT across all animals. Here, we elucidate the MZT of a non-bilaterian, the cnidarianHydractinia symbiolongicarpus. Using parallel poly(A)-selected and non poly(A)-dependent RNA-seq approaches, we find that the Hydractinia MZT is composed of regulatory activities similar to many bilaterians, including cytoplasmic readenylation of maternally contributed mRNA, delayed genome activation, and separate phases of maternal mRNA deadenylation and degradation that likely depend on both maternally and zygotically encoded clearance factors, including microRNAs. But we also observe massive upregulation of histone genes and an expanded repertoire of predicted H4K20 methyltransferases, aspects thus far particular to the Hydractinia MZT and potentially underlying a novel mode of early embryonic chromatin regulation. Thus, similar regulatory strategies with taxon-specific elaboration underlie the MZT in both bilaterian and non-bilaterian embryos, providing insight into how an essential developmental transition may have arisen in ancestral animals.