Figure 1.—

Mutations showing synthetic effects with septin mutations. Cells were observed directly in liquid culture medium by DIC microscopy (A–D and I–P) or streaked on plates to observe overall growth rates (E–H). (A–D) Wild-type strain JW81 and the septin-mutant strains JW267, JW289, and JW182. (I–L) Strains carrying the new mutations in otherwise wild-type backgrounds (JW399, JW403, JW406, and JW330). (M–P) The double or triple mutants (JW401, JW402, JW405, and JW321-1). Plates show the same strains. spn1 spn4 designates 81nmt1-spn1⁺ 81nmt1-spn4⁺. (B, J, K, N, and O) Cells were grown in EMM5S without thiamine and then shifted to EMM5S + thiamine at 30° for 24 hr to repress the nmt1 promoters. (A, C, L, and P) Cells were grown in YE5S at 30°. (D, I, and M) Cells were grown overnight in EMM5S at 32° and then shifted to 23° for 8 hr. (E) Cells were grown on YE5S at 23° for 5 days. (F and G) Cells were grown on EMM5S + thiamine at 36° for 3 days. (H) Cells were grown on YE5S at 30° for 2 days. Arrowheads in C, D, M, and P indicate cells that appear to have lysed; such cells are numerous in J, K, N, and O. Bars, 10 μm.