Division of Genetic Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
Dev Biol. 2011 Dec 1;360(1):173-85. doi: 10.1016/j.ydbio.2011.09.019. Epub 2011 Sep 22.
The neural crest is a stem cell-like population exclusive to vertebrates that gives rise to many different cell types including chondrocytes, neurons and melanocytes. Arising from the neural plate border at the intersection of Wnt and Bmp signaling pathways, the complexity of neural crest gene regulatory networks has made the earliest steps of induction difficult to elucidate. Here, we report that tfap2a and foxd3 participate in neural crest induction and are necessary and sufficient for this process to proceed. Double mutant tfap2a (mont blanc, mob) and foxd3 (mother superior, mos) mob;mos zebrafish embryos completely lack all neural crest-derived tissues. Moreover, tfap2a and foxd3 are expressed during gastrulation prior to neural crest induction in distinct, complementary, domains; tfap2a is expressed in the ventral non-neural ectoderm and foxd3 in the dorsal mesendoderm and ectoderm. We further show that Bmp signaling is expanded in mob;mos embryos while expression of dkk1, a Wnt signaling inhibitor, is increased and canonical Wnt targets are suppressed. These changes in Bmp and Wnt signaling result in specific perturbations of neural crest induction rather than general defects in neural plate border or dorso-ventral patterning. foxd3 overexpression, on the other hand, enhances the ability of tfap2a to ectopically induce neural crest around the neural plate, overriding the normal neural plate border limit of the early neural crest territory. Although loss of either Tfap2a or Foxd3 alters Bmp and Wnt signaling patterns, only their combined inactivation sufficiently alters these signaling gradients to abort neural crest induction. Collectively, our results indicate that tfap2a and foxd3, in addition to their respective roles in the differentiation of neural crest derivatives, also jointly maintain the balance of Bmp and Wnt signaling in order to delineate the neural crest induction domain.
神经嵴是一种存在于脊椎动物中的干细胞样群体,可产生多种不同的细胞类型,包括软骨细胞、神经元和黑色素细胞。神经嵴起源于神经板边缘,位于 Wnt 和 Bmp 信号通路的交汇处,其基因调控网络的复杂性使得诱导的最早步骤难以阐明。在这里,我们报告 tfap2a 和 foxd3 参与神经嵴诱导,并且对于该过程的进行是必需且充分的。tfap2a(mont blanc,mob)和 foxd3(mother superior,mos)双突变 mob;mos 斑马鱼胚胎完全缺乏所有神经嵴衍生组织。此外,tfap2a 和 foxd3 在神经嵴诱导之前的原肠胚形成期间表达,位于不同的、互补的区域;tfap2a 在腹侧非神经外胚层中表达,foxd3 在背侧中胚层和外胚层中表达。我们进一步表明,在 mob;mos 胚胎中 Bmp 信号被扩增,而 Wnt 信号抑制剂 dkk1 的表达增加,并且经典 Wnt 靶基因被抑制。这些 Bmp 和 Wnt 信号的变化导致神经嵴诱导的特定扰动,而不是神经板边缘或背腹模式的一般缺陷。另一方面,foxd3 的过表达增强了 tfap2a 在神经板周围异位诱导神经嵴的能力,从而忽略了早期神经嵴区域的正常神经板边界限制。尽管 tfap2a 或 foxd3 的缺失都会改变 Bmp 和 Wnt 信号模式,但只有它们的联合失活才能充分改变这些信号梯度,从而阻止神经嵴诱导。总之,我们的结果表明,tfap2a 和 foxd3 除了在神经嵴衍生物的分化中发挥各自的作用外,还共同维持 Bmp 和 Wnt 信号的平衡,以描绘神经嵴诱导域。
Development. 2009-6
Nucleic Acids Res. 2025-2-27
Development. 2024-10-15
Life Sci Alliance. 2024-6
Dev Genes Evol. 1997-3
Proc Natl Acad Sci U S A. 2010-12-15
Birth Defects Res C Embryo Today. 2009-6
Development. 2009-6
Proc Natl Acad Sci U S A. 2008-12-23