Fig. 1

Swi6 shuttles between the nucleus and cytoplasm in S. cerevisiae. To test for nucleocytoplasmic shuttling, chimeric Swi6-GFP, Cca1-GFP, or histone H2B-GFP proteins were expressed under control of a GAL1 promoter. Cells were incubated in the presence of galactose to induce expression, then incubated with glucose for 1 h to repress expression. Cells were then mated with kar1–1 mutant cells (MS739, [48]) to form heterokaryons and GFP localization observed using fluorescence microscopy (left panels). Nuclear location was determined by DAPI (middle column). Cells expressing Swi6-GFP (top row), the shuttling protein Cca1-GFP (middle row), and non-shuttling histone-H2B-GFP (bottom row) are depicted, with representative zygotes highlighted by a dashed outline. Bar, 5 μm