The neural crest is a dynamic embryonic structure that plays a major role in the formation of the vertebrate craniofacial skeleton. Neural crest formation is regulated by a complex sequence of events directed by a network of transcription factors working in concert with chromatin modifiers. The high mobility group nucleosome binding protein 1 (Hmgn1) is a nonhistone chromatin architectural protein, associated with transcriptionally active chromatin. Here we report the expression and function of Hmgn1 during Xenopus neural crest and craniofacial development. Hmgn1 is broadly expressed at the gastrula and neurula stages, and is enriched in the head region at the tailbud stage, especially in the eyes and the pharyngeal arches. Hmgn1 knockdown affected the expression of several neural crest specifiers, including sox8, sox10, foxd3, and twist1, while other genes (sox9 and snai2) were only marginally affected. The specificity of this phenotype was confirmed by rescue, where injection of Hmgn1 mRNA was able to restore sox10 expression in morphant embryos. The reduction in neural crest gene expression at the neurula stage in Hmgn1 morphant embryos correlated with a decreased number of sox10- and twist1-positive cells in the pharyngeal arches at the tailbud stage, and hypoplastic craniofacial cartilages at the tadpole stage. These results point to a novel role for Hmgn1 in the control of gene expression essential for neural crest and craniofacial development. Future work will investigate the precise mode of action of Hmgn1 in this context.

中文翻译：

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染色质修饰剂 Hmgn1 在神经嵴和颅面发育过程中的功能


神经嵴是一种动态的胚胎结构，在脊椎动物颅面骨骼的形成中起着重要作用。神经嵴的形成受到一系列复杂事件的调节，这些事件是由与染色质修饰剂协同工作的转录因子网络引导的。高迁移率基团核小体结合蛋白 1 (Hmgn1) 是一种非组蛋白染色质结构蛋白，与转录活性染色质相关。在这里，我们报告了爪蟾神经嵴和颅面发育过程中 Hmgn1 的表达和功能。 Hmgn1在原肠胚和神经胚阶段广泛表达，并在尾芽阶段的头部区域富集，特别是在眼睛和咽弓。 Hmgn1 敲低影响了几个神经嵴特异性因子的表达，包括sox8 、 s ox10 、 Foxd3和twin1 ，而其他基因（ sox9和snai2 ）仅受到轻微影响。这种表型的特异性通过救援得到了证实，注射Hmgn1 mRNA 能够恢复 morphant 胚胎中的sox10表达。 Hmgn1 突变体胚胎神经胚阶段神经嵴基因表达的减少与尾芽阶段咽弓中sox10和twist1阳性细胞数量的减少以及蝌蚪阶段颅面软骨发育不全有关。这些结果表明 Hmgn1 在控制神经嵴和颅面发育所必需的基因表达方面发挥着新作用。未来的工作将研究 Hmgn1 在这种情况下的精确作用模式。