小鼠胚胎致密化起始的调控机制  

Regulation of compaction initiation in mouse embryo

作　　者：李超波[1] 胡丽丽[1] 王振东[1] 钟淑琦[1] 雷蕾[1] 

机构地区：[1]哈尔滨医科大学组织学与胚胎学教研室,哈尔滨150081

出　　处：《遗传》2009年第12期1177-1184,共8页Hereditas（Beijing)

基　　金：国家自然科学基金项目(编号:30671025);黑龙江省留学归国人员科学技术专项资金(编号:LC07C17)资助

摘　　要：植入前小鼠胚胎的发育事件包括第一次卵裂、胚胎基因组激活、桑椹胚致密、囊胚形成。小鼠受精卵胚胎的致密化发生在8-细胞阶段晚期,致密过程中,胚胎卵裂球本身以及卵裂球之间发生了一系列的变化。这些变化包括卵裂球微绒毛以及胞质成分的极性化分布,卵裂球之间形成特殊的胞间连接。致密化是哺乳动物胚胎发育过程中的第一个细胞分化事件,即导致了内细胞团以及滋养外胚层的产生。植入后,内细胞团将发育成为胚体,滋养外胚层将发育成为胎盘等胚外组织。细胞粘附分子E-cadherin介导的胞间粘附起始了致密化。卵裂球发生粘附所需的组分在致密前已经存在,但是直至8-细胞阶段晚期连接复合体才表现出明显的粘附活性。敲除E-cadherin基因,发现母源性的E-cadherin足以介导致密。E-cadherin介导的胞间粘附是细胞粘附的第一步。文章综述了E-cadherin介导胞间粘附的具体过程以及蛋白激酶C(Protein kinase C,PKC)调控该过程的相关机制。Developmental events in preimplantation mouse embryos include the first cleavage, the activation of the embryonic genome, the compaction of the blastomeres to form morula （MO）, and the formation of the blastocyst （BL）. Compaction, the first cell differentiation event in mammalian development, occurs at the late eight-cell stage in the mouse and may be described in terms of some types of morphological change, which involve reorganization within a cell and intercellular reorganization. Surface microvilli became restricted to a few basal sites and to an externally facing （apical） pole. Prior to compaction, the blastomeres are spherical and lack specialized intercellular junctions. During compaction, the cells were flattened against one another, thus maximizing intercellular contact and obscuring intercellular boundaries. It is believed that the events of compaction have an important influence on the processes involved in blastocyst formation, namely the initiation of inner cell mass and trophectoderm differentiation. The inner cell mass will form the future embryo proper, whereas the trophectoderm cells will form only extraembryonic tissues. Compaction is initiated by E-cadherin mediated cell adhesion, which is regulated post-translationally via protein kinase C. With E-cadherin knock-out, maternal E-cadherin is able to mediate the compaction process at the morula stage. Initial adhesion is mediated by homophilic interactions between E-cadherin extracellular domains.In this review, we attempted to describe this process in detail.

关 键 词：胚胎 致密化 细胞粘附 蛋白激酶C 

分 类 号：Q954.4[生物学—动物学] TQ174.758[化学工程—陶瓷工业]