Role of Specc1l in ciliogenesis during craniofacial development

项目摘要 颅面畸形占所有先天畸形的三分之一。口面部裂隙(OFCs)是 最常见的先天性畸形，大约每700名新生儿中就有1名受到影响。OFCS是一种复杂的疾病 由多种遗传和环境因素引起。对潜在机制的不完全理解 OFCS表明，仍需要确定与其发病相关的基因。SPECC1L基因突变 已在综合征性和非综合征性唇腭裂患者中发现。综合征SPECC1L 突变聚集在第二螺旋卷曲结构域(CCD2)，这促进了这种细胞骨架蛋白的相互作用 有微管。我们最近的研究表明，带有SPECC1L-CCD2框内缺失的小鼠表现出 以显性-负性方式出现腭裂和脑外畸形。值得注意的是，OFC和脑外畸形很常见。 纤毛病的表现--人类因初级纤毛断裂而引起的疾病--但与 SPECC1L和初生纤毛之间的关系尚未见报道。除了与肌动蛋白细丝和 细胞骨架中的微管，SPECC1L定位于纤毛底部的中心周围区域，但这 ∆CCD2/∆CCD2在腭部间充质中的定位减少。此外，初级纤毛长度为 与野生型相比，舌侧和舌侧∆/∆CCD2在腭间充质和上皮中的表达均降低 上颚的颊侧面。在特定的目标1中，我将调查一种假设，即细胞内的贩运 腭间充质的缺陷会导致纤毛缩短，而纤毛的缩短会影响细胞内的信号。 腭间充质。由于IFT-A小鼠突变体Thm1aln/ALn与Spec1l具有重叠的表型 突变小鼠，包括腭裂、脑外畸形和纤毛缩短，我们假设Spec1和Thm1 基因上的相互作用。在具体目标2中，我将调查Spec1和Thm1之间的相互作用，我们 建议集中在纤毛发生上。以前的研究表明，神经脊中Thm1的条件性丢失 细胞(NCCs)产生腭间充质，导致腭裂，Spec1缺乏 导致NCC分层缺陷。我们的初步数据显示NCC的纤毛长度在 SPEC1缺乏症。因此，我们认为Spec1和Thm1之间的遗传互作是通过 NCC功能。总体而言，这项提议将揭示SPECC1L在纤毛发生中的多个方面的新角色 头面部发育。

Project Summary Craniofacial anomalies constitute a third of all congenital malformations. Orofacial clefts (OFCs) are among the most common congenital malformations, affecting approximately 1 in 700 births. OFCs are complex diseases caused by multiple genetic and environmental factors. Incomplete understanding of the mechanisms underlying OFCs suggests a continued need to identify genes that contribute to its pathogenesis. Mutations in SPECC1L have been identified in patients with syndromic and nonsyndromic cleft lip and/or palate. Syndromic SPECC1L mutations cluster in the second coiled coil domain (CCD2), which facilitates interaction of this cytoskeletal protein with microtubules. Our recent studies indicate that mice with an in-frame deletion of SPECC1L-CCD2 exhibit cleft palate and exencephaly in a dominant-negative manner. Notably, OFC and exencephaly are common manifestations of ciliopathies – human disorders which arise from disruption of primary cilia – but an association between SPECC1L and primary cilia has not been reported. In addition to association with actin filaments and microtubules in the cytoskeleton, SPECC1L localizes to the pericentriolar region at the cilia base, but this localization is diminished in Specc1l∆CCD2/∆CCD2 palatal mesenchyme. In addition, primary cilia lengths are decreased in Specc1l∆CCD2/∆CCD2 palatal mesenchyme and epithelium relative to wild-type, on both the lingual and buccal sides of the palate. In Specific Aim 1, I will investigate the hypothesis that an intracellular trafficking defect in the palatal mesenchyme results in shortened cilia and that the shortened cilia affect signaling in the palatal mesenchyme. Since the IFT-A mouse mutant, Thm1aln/aln, shares overlapping phenotypes with Specc1l mutant mice, including cleft palate, exencephaly, and shortened cilia, we hypothesize that Specc1l and Thm1 genetically interact. In Specific Aim 2, I will investigate the interaction between Specc1l and Thm1, which we propose converges on ciliogenesis. Previous studies have shown that conditional loss of Thm1 in neural crest cells (NCCs), which give rise to the palatal mesenchyme, results in cleft palate, and that Specc1l deficiency leads to NCC delamination defect. Our preliminary data shows that cilia lengths of NCCs are decreased upon Specc1l deficiency. Thus, we propose that the genetic interaction between Specc1l and Thm1 is mediated via NCC function. Overall, this proposal will reveal a novel role for SPECC1L in ciliogenesis in multiple aspects of craniofacial development.