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. 2019 Oct 21;29(20):3370–3385.e7. doi: 10.1016/j.cub.2019.08.017

Figure 3.

Figure 3

A New RhoGEF Controls Cell Intercalation during Germ-Band Extension

(A) Lateral view of a control and a CG10188 shRNA-expressing embryo at the onset (t = 0 min) of germ-band extension (GBE) and 40 min later. The dotted lines mark the distance between the pole cells and the posterior side of the embryos 40 min after the onset of GBE.

(B) Quantification of the rate of germ-band extension in control and CG10188 shRNA embryos. A significant difference was observed in CG10188 shRNA embryos (Kolmogorov-Smirnov two-sample test). p value for Kolmogorov-Smirnov two-sample test is indicated in the panel. p > 0.01.

(C) Top panels: a representative view of the extending ventro-lateral ectoderm in control and CG10188 shRNA embryos expressing Utr::GFP. Bottom panels: segmented view of the same embryos is shown. T1 transitions are depicted in green and red on the image.

(D) Cumulative sum of T1 transitions measured for control and CG10188 shRNA embryos over a period of 10 min.

(E) Percentage of embryos that hatched in control (n = 238/354 embryos), CG10188 shRNA (n = 0/243 embryos), and CG10188 shRNA, Sqh-cg10188wt shRNA (n = 86/213 embryos) conditions. The egg-hatching percentage was determined as a measurement of embryo viability (STAR Methods). The fully penetrant embryonic lethality observed in CG10188 shRNA embryos is rescued by the expression of the targeted gene refractory to the shRNA (Sqh-CG10188 shRNAR).

(F) Phylogenetic tree inferred from sequence similarity between the Drosophila CG10188 (Flybase: FBgn0032796) and its human orthologs p114RhoGEF (UniProtKB: Q6ZSZ5-4), GEF-H1 (UniProtKB: Q92974-1), p190RhoGEF (UniProtKB: Q8N1W1-1), and AKAP13 (UniProtKB: Q12802-1). Human sequences were collected from UniProt and clustered by multiple sequence alignment using ClustalOmega (nj tree, no distance correction). CG10188 exhibits a DH-PH tandem characteristic of the Dbl-RhoGEFs and a coil-coiled (CC) motif in its C-terminal region, known to be a dimerization domain in its mammalian counterparts.

Scale bars represent 50 μm (A) and 15 μm (C). Error bars, SD for (B) and SEM for (D).

See also Figure S3 and Video S4.