Sun Jian, Ha NaYoung, Liu Zhixu, Bian Qian, Wang Xudong
Department of Oral and Cranio-Maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
National Clinical Research Center for Oral Diseases, Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Shanghai, China.
Front Physiol. 2022 Apr 21;13:855959. doi: 10.3389/fphys.2022.855959. eCollection 2022.
Craniofacial morphogenesis is a complex process that requires precise regulation of cell proliferation, migration, and differentiation. Perturbations of this process cause a series of craniofacial deformities. Dlx2 is a critical transcription factor that regulates the development of the first branchial arch. However, the transcriptional regulatory functions of Dlx2 during craniofacial development have been poorly understood due to the lack of animal models in which the Dlx2 level can be precisely modulated. In this study, we constructed a Rosa26 site-directed Dlx2 gene knock-in mouse model for conditionally overexpressing Dlx2. By breeding with mice, we obtained mice, in which Dlx2 is overexpressed in neural crest lineage at approximately three times the endogenous level. The mice exhibited consistent phenotypes that include cleft palate across generations and individual animals. Using this model, we demonstrated that Dlx2 caused cleft palate by affecting maxillary growth and uplift in the early-stage development of maxillary prominences. By performing bulk RNA-sequencing, we demonstrated that Dlx2 overexpression induced significant changes in many genes associated with critical developmental pathways. In summary, our novel mouse model provides a reliable and consistent system for investigating Dlx2 functions during development and for elucidating the gene regulatory networks underlying craniofacial development.
颅面形态发生是一个复杂的过程，需要对细胞增殖、迁移和分化进行精确调控。该过程的紊乱会导致一系列颅面畸形。Dlx2是一种关键的转录因子，可调节第一鳃弓的发育。然而，由于缺乏能够精确调节Dlx2水平的动物模型，人们对Dlx2在颅面发育过程中的转录调控功能了解甚少。在本研究中，我们构建了一个Rosa26位点定向Dlx2基因敲入小鼠模型，用于条件性过表达Dlx2。通过与小鼠杂交，我们获得了小鼠，其中Dlx2在神经嵴谱系中以约内源性水平的三倍过表达。这些小鼠表现出一致的表型，包括几代人和个体动物的腭裂。使用该模型，我们证明Dlx2通过影响上颌突早期发育中的上颌生长和上抬导致腭裂。通过进行批量RNA测序，我们证明Dlx2过表达诱导了许多与关键发育途径相关的基因发生显著变化。总之，我们的新型小鼠模型为研究Dlx2在发育过程中的功能以及阐明颅面发育潜在的基因调控网络提供了一个可靠且一致的系统。
