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。Orofacial clefts（OFCs）是 最常见的先天性畸形，影响约1 700出生。OFC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表明继续需要确定有助于其发病机制的基因。SPECC 1 L突变 已在综合征和非综合征性唇腭裂患者中发现。综合征SPECC 1 L 突变聚集在第二卷曲螺旋结构域（CCD 2）中，这有助于这种细胞骨架蛋白的相互作用 与微管。我们最近的研究表明，SPECC 1 L-CCD 2框内缺失的小鼠表现出 腭裂和露脑畸形显性阴性。值得注意的是，OFC和露脑畸形是常见的 纤毛病的表现-由初级纤毛破坏引起的人类疾病-但与 SPECC 1 L与初级纤毛的关系尚未见报道。除了与肌动蛋白丝和 细胞骨架中的微管，SPECC 1 L定位于纤毛基部的中心粒周围区域，但这 在Specc 11/CCD 2/CCD 2腭间充质中的定位减少。此外，初级纤毛长度 与野生型相比，Specc 1 l BCCD 2/BCCD 2腭间充质和上皮细胞减少，舌和 上颚的颊侧。在具体目标1中，我将研究细胞内运输的假设， 腭间充质的缺陷导致纤毛缩短，而缩短的纤毛影响了 腭间充质由于IFT-A小鼠突变体Thm 1aln/aln与Specc 1 l具有重叠的表型， 突变小鼠，包括腭裂，露脑，和纤毛缩短，我们假设Specc 11和Thm 1 基因互动在具体目标2中，我将研究Specc 1 l和Thm 1之间的相互作用，我们 在纤毛发生上的一致性。以前的研究表明，神经嵴Thm 1的条件性缺失 细胞（NCCs），产生腭间充质，导致腭裂，Specc 1 l缺乏 导致NCC分层缺陷。我们的初步数据表明，NCC的纤毛长度减少， 特殊缺陷。因此，我们认为Specc 1 l和Thm 1之间的遗传相互作用是通过以下途径介导的： NCC功能。总的来说，这一提议将揭示SPECC 1 L在纤毛发生的多个方面的新作用， 颅面发育

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.