Ploidy has little effect on timing early embryonic events in the haplo-diploid wasp Nasonia.
Ploidy has little effect on timing early embryonic events in the haplo-diploid wasp Nasonia.
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DOI：
10.1002/dvg.23029
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发表时间：
2017-05
期刊：
影响因子：
--
通讯作者：
Lynch JA
中科院分区：
文献类型：
--
作者：
Arsala D;Lynch JA
核质比(N/C)在许多动物的母体-受精卵转变(MZT)中起着重要作用。在果蝇中，N/C比对细胞周期延长和合子基因组激活(ZGA)的影响已经得到了广泛的研究，单倍体胚胎在完成细胞化之前经历了额外的分裂，而三倍体胚胎通过一次分裂早熟。在这项研究中，我们开始了解单倍体黄蜂Nasonia倍性的固有差异是如何影响MZT的，以及果蝇MZT的哪些方面是保守的。虽然单倍体、二倍体和三倍体胚胎在早期胚胎发育方面存在细微的差异，但所有胚胎都在细胞周期12处细胞化。当ZGA被抑制时，二倍体雌性胚胎和单倍体雄性胚胎都经历了12次合胞分裂，并未能细胞化，直到死亡，没有进一步的分裂。我们还发现，果蝇MZT的关键成员在Nasonia中是保守的，但有新的表达模式。我们的结果表明，与果蝇相比，合子表达的基因在决定Nasonia细胞化时间方面的作用较小，而且对母体计时器的更强依赖与胚胎倍性必须发生变化的物种更相容。
The nucleocytoplasmic (N/C) ratio plays a prominent role in the maternal-to-zygotic transition (MZT) in many animals. The effect of the N/C ratio on cell-cycle lengthening and zygotic genome activation (ZGA) has been studied extensively in Drosophila, where haploid embryos experience an additional division prior to completing cellularization and triploid embryos cellularize precociously by one division. In this study, we set out to understand how the obligate difference in ploidy in the haplodiploid wasp, Nasonia, affects the MZT and which aspects of the Drosophila MZT are conserved. While subtle differences in early embryonic development were observed in comparisons among haploid, diploid, and triploid embryos, in all cases embryos cellularize at cell cycle 12. When ZGA was inhibited, both diploid female, and haploid male, embryos went through 12 syncytial divisions and failed to cellularize before dying without further divisions. We also found that key players of the Drosophila MZT are conserved in Nasonia but have novel expression patterns. Our results suggest that zygotically expressed genes have a reduced role in determining the timing of cellularization in Nasonia relative to Drosophila, and that a stronger reliance on a maternal timer is more compatible with species where variations in embryonic ploidy are obligatory.