Bni1 has a hyphal-specific function in the maintenance of Golgi integrity and localization. (A) Golgi disassembly in the bni1Δ/bni1Δ strain. The Golgi was visualized in wild-type (BWP17), bni1Δ/bni1Δ, or spa2Δ/spa2Δ cells harboring CaVRG4-GFP. Overnight cultures of were induced to form hyphae with serum and viewed after 1.5 h of hyphal induction (WT) and 2.5 h for bni1Δ/bni1Δ, spa2Δ/spa2Δ (B) bni1Δ/bni1Δ form true hyphae but are delayed. bni1Δ/bni1Δ cells were induced to form hyphae as in A but harvested after 4.5 h and stained with DAPI and calcofluor white to visualize the nuclei, and cell walls and septa, respectively. (C) Loss of Bni1 has no effect on ER morphology. The ER was visualized in wild-type or bni1Δ/bni1Δ yeast or hyphal cells, harboring pER-GFP. (D) Loss of Golgi puncta in hyphal but not yeast bni1Δ mutant cells. An overnight culture of the bni1Δ/bni1Δ strain harboring VRG4-GFP was diluted and grown into logarithmic phase at 30°C and harvested for microscopy (time, 0 min). These cells were induced to form hyphae and samples were collected at the indicated time points for the visualization of CaVrg4-GFP distribution. Bars, 5 μm.