Early HRas^V12 expression in epithelial cells induces cell extrusion.

<p>(A) Lateral fluorescent images of transgenic <i>krt4</i>-GFP embryos at 4.5 hpf, 12 hpf and 3 dpf. (B) Schematic of the Tol2 flanked:<i>krt4</i>:RFP-HRas^V12 construct+transposase one-cell stage injection resulting in mosaic RFP-HRas expression by 24 hpf (black hexagons). (C) (i) Lateral fluorescent image of a 24 hpf live H-Ras^V12 expressing embryo. (ii) High-magnification view of the inset in (i) indicating the apical cell extrusion phenotype (white arrow). (D) Fluorescent images of live 24 hpf <i>krt4</i>:GFP transgenic embryos injected with either control MO (Top) or Krt4 MO (bottom dashed outline) at 24 hpf illustrating that the <i>krt4</i> MO reduces transgene levels in a stable transgenic line. (E) Fluorescent images of live 24 hpf embryos transiently expressing HRas^V12 injected with either control MO or <i>krt4</i> MO illustrating that the <i>krt4</i> MO reduces transgene levels in embryos with mosaic transgene expression. (F) Quantification of cell extrusion (one representative graph shown n = 3) of HRas^V12 expressing cells from control MO and Krt4 MO injected embryos shows a significant decrease in the cell extrusion in embryos injected with the Krt4 MO. **** = p<.0001.