Hybridization led to a rewired pluripotency network in the allotetraploid Xenopus laevis.
Hybridization led to a rewired pluripotency network in the allotetraploid Xenopus laevis.
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作者：
Phelps WA;Hurton MD;Ayers TN;Carlson AE;Rosenbaum JC;Lee MT
受精后，母体对卵子的贡献因子开始向多能性转变，产生胚胎干细胞，这在很大程度上是通过激活胚胎基因组的从头转录。不同的机制协调动物之间的这种过渡，这表明普遍的监管重塑塑造了发展的最早阶段。在这里，我们表明，哺乳动物多能性重编程因子OCT 4和SOX 2的母系同源物发散激活非洲爪蟾的两个亚基因组，非洲爪蟾是一种异源四倍体，起源于1800万年前两个二倍体物种的杂交。虽然大多数基因被保留为两个同源异型拷贝，但我们发现它们中的大多数在早期胚胎中经历不对称激活。染色质可及性分析和CUT&RUN修饰的组蛋白和转录因子结合揭示了亚基因组之间的预测增强子结构的广泛差异，这可能是由于异源四倍体引起的基因组破坏。但与二倍体X.当组合不同的同源物贡献时，热带鱼类和斑马鱼显示出胚胎基因表达水平的广泛保守性，这意味着在杂交后的基因组不稳定性中，在核心脊椎动物多能性转录程序中维持剂量的强选择。
After fertilization, maternally contributed factors to the egg initiate the transition to pluripotency to give rise to embryonic stem cells, in large part by activating de novo transcription from the embryonic genome. Diverse mechanisms coordinate this transition across animals, suggesting that pervasive regulatory remodeling has shaped the earliest stages of development. Here, we show that maternal homologs of mammalian pluripotency reprogramming factors OCT4 and SOX2 divergently activate the two subgenomes of Xenopus laevis, an allotetraploid that arose from hybridization of two diploid species ~18 million years ago. Although most genes have been retained as two homeologous copies, we find that a majority of them undergo asymmetric activation in the early embryo. Chromatin accessibility profiling and CUT&RUN for modified histones and transcription factor binding reveal extensive differences in predicted enhancer architecture between the subgenomes, which likely arose through genomic disruptions as a consequence of allotetraploidy. However, comparison with diploid X. tropicalis and zebrafish shows broad conservation of embryonic gene expression levels when divergent homeolog contributions are combined, implying strong selection to maintain dosage in the core vertebrate pluripotency transcriptional program, amid genomic instability following hybridization.
影响因子：
3.3
作者：
Endo Y;Kamei KI;Inoue-Murayama M
通讯作者：
Inoue-Murayama M