Role of actin cytoskeleton regulators in craniofacial development and disease

描述（由申请人提供）：神经嵴是脊椎动物胚胎发生过程中广泛迁移的独特细胞群。特别有趣的是，颅神经嵴（CNC）细胞在整个面部迁移，形成大部分颅面骨骼。它们在增殖、迁移或存活方面的缺陷会导致许多疾病和出生缺陷，包括唇裂/腭裂、特杰-柯林斯综合征和迪乔治综合征。尽管最近在了解神经嵴发育方面取得了进展，但神经嵴迁移的机制仍不清楚。因此，研究它们的迁移行为及其对肌动蛋白细胞骨架的调控对了解先天性颅面疾病的基础至关重要。通过微阵列筛选，我发现了多个主要在神经嵴细胞中表达的肌动蛋白细胞骨架调节因子（ACR）基因。我的初步研究表明Myosin-X和Caldesmon都是通过调节细胞形态和膜突起来调节CNC细胞迁移的关键。基于这些发现，我假设神经嵴细胞是通过特定的acr来实现其独特的迁移能力，以快速和精确地控制

DESCRIPTION (provided by applicant): Neural crest is a unique population of cells that migrate extensively during vertebrate embryogenesis. Of particular interest, cranial neural crest (CNC) cells migrate throughout the face to form most of the craniofacial skeleton. Defects in their proliferation, migration, or survival lead to numerous diseases and birth defects, including cleft lip/palate, Treacher-Collins syndrome, and DiGeorge syndrome. Despite recent progress in understanding aspects of neural crest development, the mechanisms underlying neural crest migration are still unclear. Thus, studying their migratory behavior and the regulation of actin cytoskeleton therein is crucial for understanding the basis of congenital craniofacial disorders. From a microarray screen, I have identified multiple actin cytoskeleton regulator (ACR) genes that are predominantly expressed in neural crest cells. My preliminary studies reveal that Myosin-X and Caldesmon are both critical for proper CNC cell migration via regulating cell morphology and membrane protrusions. Based on these findings, I hypothesis that neural crest cells achieve their unique migratory ability through specific ACRs to rapidly and precisely control their cytoskeletal dynamics. In this proposal, I will investigate the mechanism of neural crest migration by further analyzing the activities of these ACRs, and establishing their physical and functional interactions with actin structures. Specifically, I will combine classical embryology techniques with modern cell biology, biochemistry, and in vivo microscopy to study the dynamic arrangements of actin cytoskeleton during CNC migration and examine how ACRs in the neural crest regulate this process. Experiments will be carried out in frog and chick, taking into account the advantages of both model systems: simple gene and tissue manipulation in frog, and high-resolution imaging and late stage electroporation in chick. The following specific aims will be performed: 1) Examine the dynamics of actin cytoskeleton during normal neural crest migration by real time imaging. 2) Determine the role of Myosin-X and Caldesmon in regulating actin dynamics during CNC migration. 3) Functionally characterize Cdc42ep1 and additional candidate genes identified in the microarray screen for their roles in neural crest development. 4) Determine functional and physical interactions between ACRs in CNC migration.