Fig. 2

Diverse nuclear shapes of early embryonic lineages in mouse blastocysts. A total of 16 E4.5 blastocysts were analyzed for expression of Nanog, Oct-3/4, Gata4, and Gata6 by confocal immunofluorescence microscopy. a Examples of immunostaining of representative blastocysts. Nanog and Oct-3/4 highlight the ICM; Gata4 staining indicates the nuclei of the primitive endoderm; Gata6 marks both the trophectoderm and the primitive endoderm. b Sequential confocal sections taken of a representative blastocyst show the larger and somewhat irregular shape of the nuclei of cells of the ICM, which immunostain positively for Nanog. c The dimensions of the nuclei of cells of pluripotent ICM (positive immunostaining for Oct3/4 +, negative for Gata6 -), primitive endoderm (GATA4 +), and trophectoderm (GATA6 +, GATA4 -) were measured using confocal sectioning of the blastocysts. The values are presented as mean ± s.d. The changes in nuclear dimensions between undifferentiated (ICM) and differentiated cells were found to be statistically significant for the x- (*) and y-dimensions (**) (P < 0.0001). d Nuclear volume for the cells was calculated. Statistical significance (*P < 0.0001) was found between undifferentiated (Oct-3/4-positive and Gata6-negative immunostaining) compared to differentiated cells, both primitive endoderm and trophectoderm. e Schematic 3D models of the nuclei of the cells in the E4.5 embryos were constructed using the metrics, as described in “Methods”