Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, 411008, India.
Institute of Science and Technology Austria, Klosterneuburg, Austria.
Nat Commun. 2021 Oct 19;12(1):6094. doi: 10.1038/s41467-021-26234-7.
Zygotic genome activation (ZGA) initiates regionalized transcription underlying distinct cellular identities. ZGA is dependent upon dynamic chromatin architecture sculpted by conserved DNA-binding proteins. However, the direct mechanistic link between the onset of ZGA and the tissue-specific transcription remains unclear. Here, we have addressed the involvement of chromatin organizer Satb2 in orchestrating both processes during zebrafish embryogenesis. Integrative analysis of transcriptome, genome-wide occupancy and chromatin accessibility reveals contrasting molecular activities of maternally deposited and zygotically synthesized Satb2. Maternal Satb2 prevents premature transcription of zygotic genes by influencing the interplay between the pluripotency factors. By contrast, zygotic Satb2 activates transcription of the same group of genes during neural crest development and organogenesis. Thus, our comparative analysis of maternal versus zygotic function of Satb2 underscores how these antithetical activities are temporally coordinated and functionally implemented highlighting the evolutionary implications of the biphasic and bimodal regulation of landmark developmental transitions by a single determinant.
合子基因组激活 (ZGA) 启动了基础细胞特性的区域化转录。ZGA 依赖于受保守 DNA 结合蛋白塑造的动态染色质结构。然而，ZGA 的开始与组织特异性转录之间的直接机制联系仍不清楚。在这里，我们研究了染色质组织者 Satb2 在斑马鱼胚胎发生过程中协调这两个过程中的作用。转录组、全基因组占有率和染色质可及性的综合分析揭示了母源沉积和合子合成的 Satb2 的相反分子活性。母源 Satb2 通过影响多能性因子之间的相互作用来阻止合子基因的过早转录。相比之下，合子 Satb2 在神经嵴发育和器官发生过程中激活相同的基因转录。因此，我们对 Satb2 的母源与合子功能的比较分析强调了这些相反的活性是如何在时间上协调和功能上实现的，突出了单一位点对半标志性发育转变的两相和双模态调控的进化意义。
