McConnell Josie, Petrie Linda, Stennard Fiona, Ryan Kenneth, Nichols Jennifer
Rowett Research Institute, Bucksburn, Aberdeen, United Kingdom.
Mol Reprod Dev. 2005 Aug;71(4):399-404. doi: 10.1002/mrd.20318.
T-box genes are a highly conserved family of genes encoding transcription factors, which share a conserved DNA binding domain (the T-box). Appropriate temporal and spatial expression of this gene family is critical for gastrulation and organogenesis in a number of species. The T-box containing gene Eomesodermin was first identified in Xenopus, where it plays a critical role in mesoderm formation. In situ analyses in mice have described the expression patterns of the mouse ortholog of this gene mEomesodermin (mEomes) at the time of implantation and during fetal development. Additional studies involving the disruption of the mEomes gene, have demonstrated an additional role for mEomes in trophoblast formation. However, these analyses did not address the possibility that maternally encoded or pre-blastocyst zygotic transcription of mEomes may also contribute to embryonic development. We show here that mEomes mRNA is present prior to blastocyst formation, and that the protein product of mEomes is associated with nuclear DNA during oocyte development and persistently localizes within all nuclei of the preimplantation embryo until the early blastocyst stage. mEomes protein is associated with the meiotic spindle in the unfertilized egg and with the mitotic spindle at each cell division. Our results are consistent with mEomesodermin having a role in early preimplantation development and inner cell mass formation in addition to its function in the trophoblast lineage.
T-box基因是一个高度保守的基因家族，编码转录因子，它们共享一个保守的DNA结合结构域（T-box）。该基因家族在许多物种中，其适当的时空表达对于原肠胚形成和器官发生至关重要。含T-box的基因Eomesodermin最初是在非洲爪蟾中发现的，它在中胚层形成中起关键作用。对小鼠的原位分析描述了该基因的小鼠直系同源基因mEomesodermin（mEomes）在植入时和胎儿发育期间的表达模式。涉及破坏mEomes基因的其他研究表明，mEomes在滋养层形成中还有额外作用。然而，这些分析没有探讨mEomes的母系编码或囊胚前合子转录也可能有助于胚胎发育的可能性。我们在此表明，mEomes mRNA在囊胚形成之前就已存在，并且mEomes的蛋白质产物在卵母细胞发育过程中与核DNA相关联，并持续定位于植入前胚胎的所有细胞核内，直至早期囊胚阶段。mEomes蛋白在未受精卵中与减数分裂纺锤体相关，在每次细胞分裂时与有丝分裂纺锤体相关。我们的结果与Eomesodermin除了在滋养层谱系中的功能外，在植入前早期发育和内细胞团形成中发挥作用是一致的。
