The SPF27 Homologue Num1 Connects Splicing and Kinesin 1-Dependent Cytoplasmic Trafficking in Ustilago maydis
Filament formation of AB31 wild-type and AB31Δnum1 deletion strains was monitored 12–14 hours upon induction of the bE1/bW2 heterodimer. (A) AB31 wild-type cells grow as long, straight filaments; only the tip compartment is filled with cytoplasm, separated from highly vacuolated distal compartments by a septum (arrowhead). (B) AB31Δnum1 hyphae grow shorter and more curved. In AB31Δnum1, bipolar (C) and branched (D) hyphae are observed frequently. (E) Septa of AB31Δnum1 are often formed within the compartment filled with cytoplasm (arrowheads denote delocalized septum; in lower panel, Calcofluor White staining was used to visualize the septum). (F) In approx. 2.5% of hyphae delocalized septa (arrowhead) lead to empty tip compartments. Scale bars: 10 µm.