Figure 7.

Shot and Patronin Are Required for MT Organization in the Epithelial Follicle Cells

(A) Shot and Patronin co-localize at the apical cortex of the follicle cells. An optical section through the epithelia monolayer with apical at the top and basal at the bottom. See also Figure S3.

(B) Follicle cells contain multiple apical Patronin foci. Top: view of the apical region of follicle cells expressing ubi>Cherry-Patronin. Patronin does not localize to the adherens junctions marked by Armadillo (green) staining.

(C) Apical Patronin foci co-localize with MTs. MTs were marked by ubi>EB1-GFP and Jupiter-GFP. The image is a temporal merge of several frames from Movie S9.

(D) MT organization in patronin⁰⁵²⁵² and shot³ mutant follicle cell clones marked by the loss of nuclear RFP (red). Top: patronin⁰⁵²⁵² mutant cells contain many fewer microtubules than their heterozygous neighbors. Bottom: shot null mutant cells lose the apical enrichment of MTs, but retain lateral MTs. See also Figure S4.

(E) Shot protein is still enriched apically in shot^2A2 mutant follicle cells, but the protein is also diffusely distributed throughout the cytoplasm. shot^2A2 mutant cells were marked by the absence of nlsRFP.

(F) Shot is not required for the apical recruitment of Patronin in the follicle cells. shot³ mutant cells were marked by the absence of nlsRFP.

(G) Patronin protects microtubule minus ends from the depolymerizing kinesin KLP10A in the follicle cells. The removal of KLP10A from patronin⁰⁵²⁵² mutant cells partially rescues the loss of MTs caused by the patronin mutant alone. Mutant cells were marked by the absence of nlsGFP (patronin) and nlsRFP (klp10A). Double-mutant cells lack both GFP and RFP.

(H) Mutation of klp10A does not rescue the MT phenotype of shot³ mutant clones. Double-mutant cells were marked by the absence of nlsRFP (klp10A) and by the loss of Shot staining (bottom).

(I) A model showing how Shot exclusion by Par-1 generates the polarized MT cytoskeleton in the oocyte. Par-1 is localized to the posterior of the oocyte, where it inhibits the association of Shot with the actin-rich cortex. Shot recruits Patronin to the anterior and lateral cortex to stabilize free MT minus ends and induce the formation of ncMTOCs that are the source of the MTs that localize oskar mRNA.

Scale bars represent 10 μm.