Lewis Jessica L, Bonner Jennifer, Modrell Melinda, Ragland Jared W, Moon Randall T, Dorsky Richard I, Raible David W
Molecular and Cellular Biology Program, University of Washington School of Medicine, Seattle, WA 98195, USA.
Development. 2004 Mar;131(6):1299-308. doi: 10.1242/dev.01007. Epub 2004 Feb 18.
While Wnt/beta-catenin signaling is known to be involved in the development of neural crest cells in zebrafish, it is unclear which Wnts are involved, and when they are required. To address these issues we employed a zebrafish line that was transgenic for an inducible inhibitor of Wnt/beta-catenin signaling, and inhibited endogenous Wnt/beta-catenin signaling at discrete times in development. Using this approach, we defined a critical period for Wnt signaling in the initial induction of neural crest, which is distinct from the later period of development when pigment cells are specified from neural crest. Blocking Wnt signaling during this early period interfered with neural crest formation without blocking development of dorsal spinal neurons. Transplantation experiments suggest that neural crest precursors must directly transduce a Wnt signal. With regard to identifying which endogenous Wnt is responsible for this initial critical period, we established that wnt8 is expressed in the appropriate time and place to participate in this process. Supporting a role for Wnt8, blocking its function with antisense morpholino oligonucleotides eliminates initial expression of neural crest markers. Taken together, these results demonstrate that Wnt signals are critical for the initial induction of zebrafish neural crest and suggest that this signaling pathway plays reiterated roles in its development.
虽然已知Wnt/β-连环蛋白信号通路参与斑马鱼神经嵴细胞的发育，但尚不清楚哪些Wnt蛋白参与其中，以及它们在何时发挥作用。为了解决这些问题，我们使用了一种转基因斑马鱼品系，该品系可诱导抑制Wnt/β-连环蛋白信号通路，并在发育的不同时间抑制内源性Wnt/β-连环蛋白信号通路。通过这种方法，我们确定了Wnt信号在神经嵴初始诱导过程中的关键时期，这与神经嵴产生色素细胞的后期发育阶段不同。在此早期阶段阻断Wnt信号会干扰神经嵴的形成，但不会阻断背侧脊髓神经元的发育。移植实验表明，神经嵴前体细胞必须直接转导Wnt信号。关于确定哪个内源性Wnt蛋白负责这个初始关键时期，我们发现wnt8在适当的时间和位置表达，从而参与这一过程。用反义吗啉代寡核苷酸阻断其功能可消除神经嵴标志物的初始表达，这支持了Wnt8的作用。综上所述，这些结果表明Wnt信号对于斑马鱼神经嵴的初始诱导至关重要，并表明该信号通路在其发育过程中发挥了反复作用。
