Fig 2: AJ mutants fail at both planar and perpendicular telophase correction.(A) Movie stills of Ctnna1912 RFP+ mitotic cell, annotated as in Figure 3A. While the presence of basal contact (open arrowhead) would predict planar correction, this division remains oblique when reevaluated 1h later. (B) Cumulative frequency distribution of division angles from E16.5 live imaging experiments of Ctnna1912 RFP+ and wild-type littermates; n values indicate cells imaged from three embryos images in two separate sessions. (C) Division orientation at anaphase onset (f) and 1h later (?) for Ctnna1912 knockdown and wild-type littermates, plotted from data in (B). Ctnna1912 RFP+ cells show no obvious correction pattern. (D) Cumulative frequency distribution of division orientation at anaphase onset (f) and 1hrpost-anaphase (?) for RFP+ and RFP- populations, from movies of Vcl3466 mosaic tissue; n indicates divisions from four embryos imaged in three separate sessions. (E) Data from (D) depicting orientation at anaphase onset (f) and 1h later (?) for RFP- and RFP+ cells. RFP- controls sort anaphase orientation (f) into bimodal distribution within 1h(?) in a basal-contact dependent manner; Vcl3466 RFP+ cells display minimal change, or correct irrespective of basal contact. (F) An obliquely-oriented Afdn2711 RFP+ cell fails to reorient, while losing basal contact (open arrowhead). (G) Timelines of division orientation at 5 min intervals from movies of Afdn2711 RFP- (black) and RFP+ (red) for 15 representative cells per group. Telophase reorientation establishes bimodal distribution within ~30 min in RFP- control cells that enter anaphase at oblique angles, while RFP+ cells fail to demonstrate any sorting behavior over a full hour following anaphase onset. (H) Cumulative frequency distributions of division orientation from E16.5 live imaging of Afdn2711 RFP+ and wild-type littermates; n indicates observed divisions from three embryos imaged in two separate sessions. (I) Radial change (f-?) for oblique anaphase divisions (30°-60°) in several shRNA conditions. While loss of LGN allows for normal telophase correction, Afdn, Ctnna1, and Vcl knockdown results in incoherent or minimal radial change; n indicates number of divisions from 3 to 6 individuals embryos images in 2–4 technical replicates. (J) Division orientation at anaphase onset (f) and one hour later (?) for Afdn2711 RFP+ and RFP- cells, plotted from data in (C). RFP- controls correct into a bimodal distribution, while RFP+ cells reorient randomly. Scale bars, 10 µm. P values determined by Kolmogorov-Smirnov test (B,D,H) or student’s t-test (I). *p<0.05, **p<0.01, ***p<0.001. See also Figure 6—figure supplement 1.Figure 6—source data 1.Original measurements used to generate panels B, C, D, E, G, H, I, J.

Fig 3: Planar telophase correction limits precocious and sustained differentiation and biases clones towards symmetric cell divisions.(A) (top) z-projection stills from a movie of an E14.5 mitotic cell, annotated as in Figure 1E. (B) Cumulative frequency distribution of division angles from live imaging experiments of E14.5 embryos at anaphase onset (blue; f) and 1h later (black; ?); n indicates number of divisions from 3 embryos across two independent sessions. (C) Data from (B) depicting division orientations at telophase and 1h later, sorted based on retention/loss of basal contact throughout cell division. Connecting lines demonstrate that, at E14.5, planar correction occurs in a contact dependent manner, while mitoses that lose contact demonstrate no obvious pattern of correction. (D) Sagittal section of E14.5 epidermis with mosaic Afdn2711 H2B-RFP transduction. Regions of high infection display increased stratification, as demonstrated by K10 (green) positivity. (E-F) Quantification of epidermal differentiation from E14.5 sagittal sections. Afdn (E) or Ctnna1 (F) knockdown increases suprabasal cell density, suggesting precocious differentiation. (G) (top) Graphical depiction of clonal lineage tracing strategy; (bottom) Representative images of E17.5 sagittal sections from lineage tracing experiments stained with GFP (green), K10 (red), and RFP/ß4-integrin (gray). Afdn2711 knockdown clones display asymmetric (suprabasal) bias. (H) Clonal density arrays representing all evaluated clones (except delamination events) from experiments outlined in (G). The proportion of total clones for each possible combination of basal/suprabasal cells is coded on a color spectrum correlating to 0–12% of all clones. (I) Quantification of suprabasal (SB):basal cell ratio for individual clones. Knockdown of Afdn results in a higher ratio of SB cells in individual clones compared to wild-type littermates. Scale bars, 5 µm (A), 25 µm (D). *p<0.05, ***p<0.001, determined by Kolmogorov-Smirnov test (B) or student’s t-test (F). See also Figure 8—figure supplement 1.Figure 8—source data 1.Original measurements used to generate panels B, C, F, H , I.