<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Symmetry breaking in mouse development"^^ . "Unlike many other species, where the body plan is already pre-patterned in the oocyte or upon fertilization, in the early mouse embryo there is no asymmetry up to 8-cell stage when all cells in the embryo have the same morphology and developmental potential. As development proceeds initially identical cells of the embryo segregate into two distinct cell lineages: trophectoderm (TE) and the inner cell mass (ICM) (Wennekamp et al., 2013; Rossant and Tam, 2009; Yamanaka et al., 2006). While both apical-basal cell polarity (Hirate et al., 2013; Alarcon, 2010) and cell-cell adhesion (Stephenson, Yamanaka and Rossant, 2010) are required for this differentiation, the decisive cue that breaks symmetry between the cells and is sufficient for specifying the first cell fate remains to be identified (Wennekamp et al., 2013).\r\nTo understand the mechanism underlying the symmetry breaking in the mouse embryo, in this study I have established a new experimental system in which a blastomere isolated at the 8-cell stage (1/8th blastomere) recapitulates the first lineage segregation between TE and ICM during its development into 4/32th mini-blastocyst. Using live-imaging and quantitative image analysis, I identified that inheritance of the apical domain during 1/8th-to-2/16th-cell stage division allows for predicting the process leading to TE fate specification. The majority of 8-cell blastomeres undergo asymmetric division defined by the differential segregation of the apical domain among daughter cells. In the 8-cell stage embryo, the apical domain, emerging at the center of the contact-free surface of the blastomere, recruits microtubule organizing centers to the sub-apical region, thereby forming one of the acentrosomal spindle poles and inducing the asymmetric division. After asymmetric 8-to-16-cell stage division, all cells that inherit the apical domain express a TE marker, Cdx2. In contrast, apolar cells can either acquire ICM fate, as previously described, or, if positioned on the embryo surface, form a new apical domain and turn on Cdx2. Thus, contrary to the previous model (Johnson and Ziomek, 1981b), cell fate is determined by its position within the embryo, but not by the division pattern. Finally, using 1/8th blastomere, I showed that cell contact, not mediated by Cdh1, facilitates cellular symmetry breaking and directs the apical domain formation in the center of the contact-free surface, and that the inheritance of this apical domain predicts the acquisition of TE fate."^^ . "2016" . . . . . . . "Ekaterina"^^ . "Korotkevich"^^ . "Ekaterina Korotkevich"^^ . . . . . . "Symmetry breaking in mouse development (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Symmetry breaking in mouse development (PDF)"^^ . . . "Thesis_Ekaterina_Korotkevich.pdf"^^ . . . "Symmetry breaking in mouse development (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Symmetry breaking in mouse development (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Symmetry breaking in mouse development (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Symmetry breaking in mouse development (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #21810 \n\nSymmetry breaking in mouse development\n\n" . "text/html" . . . "500 Naturwissenschaften und Mathematik"@de . "500 Natural sciences and mathematics"@en . .