Deciphering the role of mediator of ErbB2 driven cell motility (Memo1) in regulat

描述(由申请人提供)：颅面结构的胚胎发育需要一系列紧密协调的细胞和形态事件。这些包括对细胞增殖、生长、迁移和分化的调控。这些过程对扰动的敏感性从影响头部及相关结构的人类出生缺陷的高发生率中可见一斑(约75%的出生缺陷具有颅面部成分)，其中最常见的是口面部裂伤(约1：600-1,000例活产)。这些缺陷将使患者的生活质量显著下降，并带来与治疗相关的重大经济负担。为了更好地了解并最终在产前预防这些疾病，需要对在正常颅面发育过程中控制上述细胞过程的基因进行精确的了解。为此，通过基于ENU的突变筛选，我们已经确定ErbB2驱动的细胞运动调节因子1(Memo1)是一种新的调节颅面发育多个方面的因子，包括颅底和腭部的适当形成。有趣的是，Memo1enu/enu突变体中的大多数受影响的结构都来自于颅神经脊细胞，这意味着Memo1在这个胚胎干细胞群体中发挥了作用。以前的研究发现，Memo1是将细胞外信号调节为细胞内反应的重要组成部分，如细胞迁移和增殖。然而，Memo1缺失的胚胎是早期胚胎致死的，排除了对Memo1在头面部发育中的S作用的任何分析。因此，我们的Memo1 enu等位基因为破译Memo1在这些过程中的作用提供了一个独特的模型。我们的总体目标是使用两个目标来精确描述Memo1在颅面发育过程中的机制作用。(目的1)首先，通过将我们的Memo1 enu等位基因与Memo1零等位基因相结合，我们将产生一个等位基因系列，作为一个方便的遗传模型系统来剖析Memo1在颅面发育中的S细胞角色。所产生的等位基因组合将被用于分析大体颅面发育和颅神经脊细胞生物学，包括更详细的神经脊细胞迁移的体外检查。(目的2)其次，由于Memo1在多个头面部组织中表达，我们将产生Memo1的条件等位基因，允许其组织特异性缺失。鉴于我们的ENU突变体中的大多数缺陷是在源自颅神经脊细胞的结构中发现的，我们将通过产生神经脊特异缺失Memo1的突变体来具体评估Memo1在该组织中的细胞自主需求，并彻底表征这如何影响颅面发育。总而言之，Memo1最近才被认为与面部形成有关，但对该基因的进一步表征可能会让我们深入了解更广泛的基因网络，这些基因网络负责正常的人类面部形成。从长远来看，拟议的工作将有助于更详细地了解颅面发育过程，为检测和预防头面部疾病提供更明确的途径。

DESCRIPTION (provided by applicant): Embryonic development of craniofacial structures requires a tightly orchestrated series of cellular and morphological events. These include regulation of cellular proliferation, growth, migration, and differentiation. The sensitivity of thse processes to perturbation is evident by the high incidence of human birth defects affecting the head and associated structures (~75% of all birth defects have a craniofacial component), most common of which is orofacial clefting (~1:600-1,000 live births). These defects will impart a significant decrease in quality of life on those afflicted and present a major economic burden associated with treatment. To better understand and ultimately prevent these disorders prenatally a precise understanding of genes controlling the aforementioned cellular processes during normal craniofacial development is required. To this end, through an ENU based mutagenesis screen, we have identified Mediator of ErbB2-driven cell motility 1 (Memo1) as a novel regulator of multiple aspects of craniofacial development, including appropriate formation of the skull-base and palate. Interestingly, most of the affected structures in Memo1enu/enu mutants are derived from the cranial neural crest cells, implicating a role for Memo1 within this embryonic stem-cell population. Previous studies identified Memo1 as an important component in modulating extracellular cues into intracellular responses, such as cellular migration and proliferation. However, Memo1-null embryos are early embryonic lethal, precluding any analysis of Memo1's role during craniofacial development. Our Memo1 ENU-allele thus provides a unique model to decipher Memo1's role during these processes. Our general goal is to precisely characterize the mechanistic role of Memo1 during craniofacial development using two Aims. (AIM 1) First, by combining our Memo1 ENU-allele with a Memo1 null-allele, we will generate an allelic series, serving as a convenient genetic model system to dissect Memo1's cellular role during craniofacial development. The resultant allelic combinations will be utilized for analysis o gross craniofacial development and cranial neural crest cell biology, including a more detailed in vitro examination of neural crest cell migration. (AIM 2) Secondly, because Memo1 is expressed in multiple craniofacial tissues, we will generate a conditional allele of Memo1 allowing its tissu specific deletion. Given the majority of the defects in our ENU- mutant are found in structures derived from the cranial neural crest cells, we will specifically assess the cell autonomous requirements of Memo1 in this tissue by generating mutants with a neural crest specific deletion of Memo1, and thoroughly characterize how this impacts craniofacial development. In summary, Memo1 has only recently been linked with face formation but further characterization of this gene is likely to generate insight into the broader gene network responsible for normal human facial formation. In the long-term, the work proposed will contribute to a more detailed understanding of processes involved in craniofacial development, providing a clearer path towards detection and prevention of craniofacial disorders.