Department of Molecular Craniofacial Embryology and Oral Histology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
Office of Vaccines, Pharmaceuticals and Medical Devices Agency (PMDA), Japan.
Birth Defects Res. 2024 Nov;116(11):e2404. doi: 10.1002/bdr2.2404.
Mutations in genes encoding spliceosome components result in craniofacial structural defects in humans, referred to as spliceosomopathies. The SF3b complex is a crucial unit of the spliceosome, but model organisms generated through genetic modification of the complex do not perfectly mimic the phenotype of spliceosomopathies. Since the phenotypes are suggested to be determined by the extent of spliceosome dysfunction, an alternative experimental system that can seamlessly control SF3b function is needed.
To establish another experimental system for model organisms elucidating relationship between spliceosome function and human diseases, we administered Pladienolide-B (PB), a SF3b complex inhibitor, to mouse and zebrafish embryos and assessed resulting phenotypes.
PB-treated mouse embryos exhibited neural tube defect and exencephaly, accompanied by apoptosis and reduced cell proliferation in the neural tube, but normal structure in the midface and jaw. PB administration to heterozygous knockout mice of Sf3b4, a gene coding for a SF3b component, influenced the formation of cranial neural crest cells (CNCCs). Despite challenges in continuous PB administration and a high death rate in mice, PB was stably administered to zebrafish embryos, resulting in prolonged survival. Brain, cranial nerve, retina, midface, and jaw development were affected, mimicking spliceosomopathy phenotypes. Additionally, alterations in cell proliferation, cell death, and migration of CNCCs were detected.
We demonstrated that zebrafish treated with PB exhibited phenotypes similar to those observed in human spliceosomopathies. This experimental system may serve as a valuable research tool for understanding spliceosome function and human diseases.
编码剪接体成分的基因突变会导致人类颅面结构缺陷，称为剪接体病。SF3b 复合物是剪接体的关键单位，但通过遗传修饰该复合物产生的模式生物并不能完全模拟剪接体病的表型。由于表型被认为是由剪接体功能障碍的程度决定的，因此需要一种能够无缝控制 SF3b 功能的替代实验系统。
为了建立另一种用于阐明剪接体功能与人类疾病之间关系的模式生物实验系统，我们给小鼠和斑马鱼胚胎施用了 SF3b 复合物抑制剂 Pladienolide-B（PB），并评估了由此产生的表型。
PB 处理的小鼠胚胎表现出神经管缺陷和无脑畸形，伴随着神经管中的细胞凋亡和增殖减少，但中面部和颌骨结构正常。PB 给药于编码 SF3b 复合物成分的 Sf3b4 基因杂合敲除小鼠，影响颅神经嵴细胞（CNCCs）的形成。尽管 PB 在小鼠中连续给药存在挑战且死亡率较高，但它能够稳定地给药于斑马鱼胚胎，从而延长了存活时间。受影响的器官包括脑、颅神经、视网膜、中面部和颌骨，模拟了剪接体病的表型。此外，还检测到 CNCCs 的细胞增殖、细胞死亡和迁移的改变。
我们证明了 PB 处理的斑马鱼表现出与人类剪接体病相似的表型。这个实验系统可能成为理解剪接体功能和人类疾病的有价值的研究工具。
