RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification.
RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification.
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DOI：
10.7554/elife.63600
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发表时间：
2022-10-03
期刊：
影响因子：
7.7
通讯作者：
Bronner ME
中科院分区：
文献类型：
--
作者：
Hutchins EJ;Gandhi S;Chacon J;Piacentino M;Bronner ME
虽然已知神经嵴发育是通过基因调控网络（grn）的顺序激活来转录控制的，但最近的证据越来越多地表明，转录后调控在调节这些调控回路的输出中起着重要作用。利用现有的鸟类胚胎单细胞rna测序数据集来鉴定潜在的转录后调节因子，我们发现编码rna结合蛋白的Elavl1在迁移前颅神经嵴中富集。Elavl1的干扰导致神经管神经嵴过早剥离，以及与神经嵴特异性GRN相关的转录物显著减少，这些表型也与典型Wnt抑制剂Draxin的下调有关。RNA测序、RNA免疫沉淀、RNA衰减测量和邻近连接实验表明，在颅神经嵴特异性过程中，Draxin是Elavl1稳定的主要靶点，进一步支持了Elavl1敲除后神经嵴特异性表达下调主要是由于Draxin缺失的观点。重要的是，外源性德拉欣修复了Elavl1敲低观察到的颅神经嵴规格缺陷。因此，Elavl1通过稳定Draxin mRNA在维持颅神经嵴规范中起关键作用。总之，这些数据强调了神经嵴规范GRN的转录后调节的重要交叉点。随着胚胎的发育，不同的遗传程序被激活，赋予细胞群特定的生物学身份，这将决定它们的命运。例如，当某些基因被激活时，胚胎最外层的细胞开始迁移到体内的最终目的地。在那里，这些“神经嵴细胞”将有助于面部的骨骼和软骨、色素皮肤斑点以及肠道的肌肉或神经。当负责神经嵴识别的基因活跃时，它们的指令被复制到“RNA分子”中，然后将这些信息传递给蛋白质构建结构。RNA传递信息的效果取决于它在细胞内存在的时间。某些rna结合蛋白可以控制这一过程，但尚不清楚这种调节是否以及如何在神经嵴细胞中发生。因此，在他们的工作中，Hutchins等人专注于识别参与神经嵴识别的rna结合蛋白。对鸡胚胎遗传数据的探索性搜索表明，即使在它们开始迁移之前，神经嵴细胞最近获得了它们的身份，产生了大量的rna结合蛋白Elavl1。此外，当胚胎被剥夺这种蛋白质时，这些细胞的行为也不正常：它们过早地离开了外层，然后关闭了对它们的身份至关重要的基因。对缺乏Elavl1的神经嵴细胞的遗传学研究表明，这种影响是由于失去了由Draxin基因产生的RNA分子。在缺少Elavl1的突变胚胎中引入额外的Draxin来源足以恢复正常的神经嵴行为。进一步的生化实验表明，在缺乏Elavl1的情况下，Draxin的RNA迅速衰减。这表明这种蛋白质通常允许Draxin的RNA存在足够长的时间来传递信息。这些结果揭示了一种控制神经嵴身份和行为的新机制。由于成年期的许多癌症都是由神经嵴细胞的后代引起的，Hutchins等人希望这一知识可以在未来改善治疗方法。
While neural crest development is known to be transcriptionally controlled via sequential activation of gene regulatory networks (GRNs), recent evidence increasingly implicates a role for post-transcriptional regulation in modulating the output of these regulatory circuits. Using available single-cell RNA-sequencing datasets from avian embryos to identify potential post-transcriptional regulators, we found that Elavl1, which encodes for an RNA-binding protein with roles in transcript stability, was enriched in the premigratory cranial neural crest. Perturbation of Elavl1 resulted in premature neural crest delamination from the neural tube as well as significant reduction in transcripts associated with the neural crest specification GRN, phenotypes that are also observed with downregulation of the canonical Wnt inhibitor Draxin. That Draxin is the primary target for stabilization by Elavl1 during cranial neural crest specification was shown by RNA-sequencing, RNA immunoprecipitation, RNA decay measurement, and proximity ligation assays, further supporting the idea that the downregulation of neural crest specifier expression upon Elavl1 knockdown was largely due to loss of Draxin. Importantly, exogenous Draxin rescued cranial neural crest specification defects observed with Elavl1 knockdown. Thus, Elavl1 plays a critical a role in the maintenance of cranial neural crest specification via Draxin mRNA stabilization. Together, these data highlight an important intersection of post-transcriptional regulation with modulation of the neural crest specification GRN. As an embryo develops, different genetic programs become activated to give cell populations a specific biological identity that will shape their fate. For instance, when certain sets of genes get switched on, cells from the outermost layer of the embryo start to migrate to their final destination within the body. There, these ‘neural crest cells’ will contribute to bones and cartilage in the face, pigmented skin spots, and muscles or nerves in the gut. When genes responsible for the neural crest identity are active, their instructions are copied into an ‘RNA molecule’ which will then relay this information to protein-building structures. How well the RNA can pass on the message depends on how long it persists within the cell. Certain RNA-binding proteins can control this process, but it is unclear whether and how this regulation takes place in neural crest cells. In their work, Hutchins et al. therefore focused on identifying RNA-binding proteins involved in neural crest identity. Exploratory searches of genetic data from chick embryos revealed that, even before they started to migrate, neural crest cells which have recently acquired their identity produced large amounts of the RNA-binding protein Elavl1. In addition, these cells did not behave normally when embryos were deprived of the protein: they left the outer layer too soon and then switched off genes important for their identity. Genetic studies of neural crest cells lacking Elavl1 revealed that this effect was due to having lost the RNA molecule produced from the Draxin gene. Introducing an additional source of Draxin into mutant embryos missing Elavl1 was enough to restore normal neural crest behaviour. Further biochemical experiments then showed that the RNA for Draxin decayed quickly in the absence of Elavl1. This suggests that the protein normally allows Draxin’s RNA to persist long enough to pass on its message. These results reveal a new mechanism controlling the identity and behaviour of the neural crest. Since many cancers in adulthood arise from the descendants of neural crest cells, Hutchins et al. hope that this knowledge could lead to improved therapies in the future.
影响因子：
2.7
作者：
Steventon B;Mayor R
通讯作者：
Mayor R