MORPHOGENESIS IN THE MOUSE PREIMPLANTATION EMBRYO

许多常见的出生缺陷被认为是由于缺陷造成的 形态发生。 形态发生涉及细胞与细胞的接触和细胞 表面细胞骨架相互作用。 我们的长期目标是阐明 细胞与细胞接触与细胞表面细胞骨架之间的关系 哺乳动物胚胎正常形态发生过程中的相互作用。 我们 提议研究存在于最简单的关系之一中的这种关系 可用于哺乳动物形态发生实验的模型，即 小鼠囊胚的体外形成。 囊胚形成需要 两个相互关联的事件，1) 空化和 2) 分化 滋养外胚层和内细胞团（ICM）。 该项目重点关注 空化的形态发生细节。 我们提出了一个新的模型 空化现象具有以下特点： 1. 空化现象 取决于细胞质细胞器（液滴 和线粒体），其仅限于并列的细胞表面 桑椹胚，2.这些细胞器的皮层定位到并列细胞 表面取决于，a.自由细胞之间质膜结构域的差异 和并列的细胞表面，b．细胞骨架元件之间的相互作用 和并列细胞表面的质膜域（即细胞 表面-细胞骨架相互作用），3.液滴由脂质和 它们通过伴随的线粒体的分解代谢与生产耦合 新生囊胚腔液。 该项目的具体目标是 特别注意检查这些提议功能的有效性 考虑到细胞表面-细胞骨架相互作用的作用并提出 皮质定位和脂质分解代谢中的质膜结构域 新生囊胚液的来源。 实验将需要使用 抗血清（免疫荧光和免疫过氧化物酶技术） 选择性地标记特定的膜域以及治疗方法 会破坏细胞骨架元件、膜域和细胞 表面细胞骨架相互作用；结果将通过光和 电子显微镜。 将通过细胞化学检查脂质分解代谢， 光和电子放射自显影和形态测量分析 微观层面。

Many common birth defects are believed to result from defective morphogenesis. Morphogenesis involves cell-cell contacts and cell surface-cytoskeletal interactions. Our long term objective is to elucidate the relationship between cell-cell contact and cell surface cytoskeletal interactions during normal morphogenesis in the mammalian embryo. We propose to study such a relationship as it exists in one of the simplest models available for experiments on mammalian morphogenesis, namely, the formation of the mouse blastocyst in vitro. Blastocyst formation entails two interrelated events, 1) cavitation and 2) differentiation of trophectoderm and inner cell mass (ICM). This project focuses on the morphogenetic details of cavitation. We propose a new model for the onset of cavitation that incorporates the following features: 1. cavitation depends on the cortical localization of cytoplasmic organelles (droplets and mitochondria), which is restricted to apposed cell surfaces of the morula, 2. cortical localization of these organelles to apposed cell surfaces depends on, a. differences in plasma membrane domains between free and apposed cell surfaces, b. interactions between cytoskeletal elements and plasma membrane domains of apposed cell surfaces (i.e., cell surface-cytoskeletal interactions), 3. the droplets consist of lipid and their catabolism by the attendant mitochondria is coupled to the production of nascent blastocoele fluid. The specific aims of this project are to examine the validity of these proposed features with special attention given to the role of cell surface-cytoskeletal interactions and apposed plasma membrane domains in cortical localization and of lipid catabolism as a source of nascent blastocoele fluid. The experiments will entail the use of antisera (immunofluorescence and immunoperoxidase techniques) that will selectively label specific membrane domains together with treatments that will disrupt cytoskeletal elements, membrane domains and cell surface-cytoskeletal interactions; results will be assessed by light and electron microcopy. Lipid catabolism will be examined by cytochemical, autoradiographic and morphometric analyses at the light and electron microscopic levels.