Lack of Shs1 disrupts septin collar organization at the EM level. Samples of SHS1⁺ and shs1Δ cells were processed and examined by EM and EM tomography as described in Murray (2008) and in Materials and methods. (A) Grazing thin section of SHS1⁺ cell. (B) The same image as in A with neck filaments traced in black. (C) A slice through a tomogram of an shs1Δ cell; note the disorganized filaments at the bud neck. (D) The same slice as in C with filaments traced in black.