Fig. 2.

NFPs regulate oriented cell division (OCD) and directional migration. Cardiomyocytes of single-layer myocardium undergo perpendicular OCD in A and parallel division in B. The mitotic spindles are identified by acetylated α-tubulin and endocardial cells are identified by endomucin. (C) The angle between mitotic spindles and the myocardial plain was measured and compared between control and MDKO at about E9.25. The patterns of mitotic spindle orientation between control and MDKO are different based on χ² analysis. (D) Via single-cell lineage tracing, the GFP-labeled iDKO clone, indicated by the white arrow, does not express Numb based on ISH. (E) The clonal patterns between control and iDKO are significantly different, and the iDKO clones contain smaller percentages of trabecular and transmural clones and higher percentage of surface clones. (F and G) The MDKO hearts display a smaller number of trabeculae and the trabeculae in MDKO are shorter than control trabeculae. White arrows indicate trabeculae. (Scale bars in A, B, and D: 20 μm and in F and G: 50 μm.)