(A) Images of fixed WT, , and embryos are shown in cycle-13 metaphase and cellularization (staged by DNA, blue) at the sections crossing the furrow

(B) Compared with WT, RhoGEF2 is more diffuse at the furrow in and embryos at cycle-13 prophase. Green, F-actin; red, RhoGEF2. (C) Line plots of RhoGEF2 (red curves) and Dlg (green curves) signal intensities (normalized to the maximum signal of each plot into a 0–1 scale) crossing the furrows (red lines in B). WT exhibited a single focused RhoGEF2 peak corresponding to the Dlg peak. In and embryos, RhoGEF2 showed unfocused peaks that did not generally correspond with the Dlg peak. (D and E) Rho1 and Diaphanous (red) are not concentrated in furrow regions lacking F-actin (green) but localize properly at regions maintaining F-actin in embryos. (F) At cycle-13 interphase, RhoGEF2 (red) is diffusely localized around the furrow, whereas Anillin (green) is localized normally (arrows). (G) Nuf shows dominant genetic interactions with components of the RhoGEF2–Rho1 pathway. Cycle-13 prometaphase or metaphase embryos (staged by DNA; blue) derived from females with different genetic background were stained with phalloidin to show the furrow structure. (), (), (), (), and () embryos display abnormal furrow morphologies (arrows indicate furrow breaks or weak furrows), whereas () embryos have relatively normal furrow morphology. Summary of phenotypic frequencies is shown in . Bars: (A and G) 10 μm; (B–F) 5 μm.<p><b>Copyright information:</b></p><p>Taken from "Nuf, a Rab11 effector, maintains cytokinetic furrow integrity by promoting local actin polymerization"</p><p></p><p>The Journal of Cell Biology 2008;182(2):301-313.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2483530.</p><p></p

In WT embryos, Nuf promotes actin polymerization at the invaginating furrow by properly localizing RhoGEF2 to the furrow, where it activates Rho1

Up-regulating actin polymerization stabilizes furrow membrane. In mutant embryos, failed RhoGEF2 recruitment results in insufficient actin polymerization. This in turn results in loss of furrow membrane integrity.<p><b>Copyright information:</b></p><p>Taken from "Nuf, a Rab11 effector, maintains cytokinetic furrow integrity by promoting local actin polymerization"</p><p></p><p>The Journal of Cell Biology 2008;182(2):301-313.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2483530.</p><p></p

(A) In untreated cycle-12 embryos, membrane (GFP-Dlg, green) is closely surrounded by F-actin (red) at the furrow

(B) 2 mM LatA or DMSO was injected at cycle-13 early prophase. GFP-Dlg–marked plasma membrane was progressively lost (arrowheads) as furrows invaginated in LatA-injected embryos (top row). Membrane loss started after most of the F-actin was lost at the furrow (middle row). (C) Furrow integrity was monitored relative to spindle spacing and dynamics (tubulin, red). Spindle fusion (asterisks) occurred where membrane (Dlg, green) was lost at the furrow. See Video 2 (available at ). Bars, 10 μm.<p><b>Copyright information:</b></p><p>Taken from "Nuf, a Rab11 effector, maintains cytokinetic furrow integrity by promoting local actin polymerization"</p><p></p><p>The Journal of Cell Biology 2008;182(2):301-313.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2483530.</p><p></p

(A and B) 1 mg/ml C3 transferase was injected at cycle-13 early prophase

(A) GFP-Dlg–marked furrow membrane (green) was progressively lost and eventually led to spindle fusions (red, asterisks). See Video 8 (available at ). (B) 2 min after C3 injection, most of the F-actin has been lost from the furrow (bottom). In contrast, membrane loss has just started (top). (C) 1 mg/ml RhoA(Q63L) was injected into embryos at cycle-13 early interphase. Green, GFP-Moesin; red, tubulin. At metaphase (18:00), normal furrow structures were maintained in the region close to injection site (arrow); however, loss of F-actin at the furrows is evident further away from the site of injection (arrowheads). See Video 9 (available at ). Bars: (A) 10 μm; (B) 5 μm; (C) 20 μm.<p><b>Copyright information:</b></p><p>Taken from "Nuf, a Rab11 effector, maintains cytokinetic furrow integrity by promoting local actin polymerization"</p><p></p><p>The Journal of Cell Biology 2008;182(2):301-313.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2483530.</p><p></p

(A) 1 mM Jasp, 2 mM LatA, or DMSO control were injected into GFP-Dlg embryos at cycle-13 early prophase (when furrow is ∼3 μm in length), and furrow invagination was followed over time at depths from −2 μm to −8 μm below the embryo surface

(B) The lengths of invaginating furrows (y axis) over time (x axis) after 1 mM Jasp or DMSO injections in A. (C) Quantification of results in A. Increases in furrow lengths (in micrometers) 8 min after Jasp ( = 5 embryos) or DMSO ( = 5 embryos) injections were analyzed. ***, P < 0.001. Error bars represent SEM. Bar, 10 μm.<p><b>Copyright information:</b></p><p>Taken from "Nuf, a Rab11 effector, maintains cytokinetic furrow integrity by promoting local actin polymerization"</p><p></p><p>The Journal of Cell Biology 2008;182(2):301-313.</p><p>Published online 28 Jul 2008</p><p>PMCID:PMC2483530.</p><p></p