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学事件。这些包括细胞增殖、生长、迁移和分化的调节。人类出生缺陷影响头部和相关结构的发生率很高（约75%的出生缺陷有颅面成分），其中最常见的是口面裂（约1:60 -1,000活产），这表明这些过程对扰动的敏感性是显而易见的。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，需要精确了解在正常颅面发育过程中控制上述细胞过程的基因。为此，通过基于ENU的突变筛选，我们发现erbb2驱动的细胞运动1 （Memo1）是颅面发育多个方面的新调节剂，包括颅底和上颚的适当形成。有趣的是，在Memo1enu/enu突变体中，大多数受影响的结构来源于颅神经嵴细胞，这暗示了Memo1在胚胎干细胞群体中的作用。先前的研究发现，Memo1是调节细胞外信号进入细胞内反应（如细胞迁移和增殖）的重要组成部分。然而，没有Memo1的胚胎是早期胚胎致死的，因此无法分析Memo1在颅面发育过程中的作用。因此，我们的Memo1 enu等位基因提供了一个独特的模型来破译Memo1在这些过程中的作用。我们的总体目标是通过两个目标精确地描述Memo1在颅面发育过程中的机制作用。首先，通过将我们的Memo1 enu等位基因与Memo1零等位基因结合，我们将生成一个等位基因系列，作为一个方便的遗传模型系统来解剖Memo1在颅面发育过程中的细胞作用。由此产生的等位基因组合将用于分析大体颅面发育和颅神经嵴细胞生物学，包括更详细的神经嵴细胞迁移的体外检查。其次，由于Memo1在多个颅面组织中表达，我们将生成一个Memo1的条件等位基因，允许其组织特异性删除。鉴于我们的ENU-突变体中的大多数缺陷是在颅神经嵴细胞衍生的结构中发现的，我们将通过产生具有神经嵴特异性缺失Memo1的突变体来专门评估该组织中Memo1的细胞自主需求，并彻底表征这如何影响颅面发育。总之，Memo1直到最近才与面部形成联系起来，但对该基因的进一步表征可能会让我们深入了解与正常人类面部形成有关的更广泛的基因网络。从长远来看，所提出的工作将有助于更详细地了解颅面发育过程，为颅面疾病的检测和预防提供更清晰的途径。

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.