Figure 6.

TIF1-deficient cells synthesize DNA more slowly than wild type, but maintain a normal macronuclear DNA content. (A) Sytox (DNA) staining of log phase vegetative cultures of wild-type (CU428) and homozygous TIF1::neo knockout (TXk202) strains. White arrows point to extranuclear DNA-staining bodies in TIF1-deficient cells. These structures were absent in cells transferred into starvation media (unpublished data). (B) Flow cytometry of synchronized wild-type and TIF1 knockout strains reveals a diminished rate of DNA synthesis in TIF1-deficient cells. Stationary phase/starved cultures were refed and stained with propidium iodide at 1-h intervals for FACS analysis. The FACS profiles for synchronized wild-type (CU428, purple) and TIF1 knockout (TXk202, pink) cultures were overlaid, the area of overlap appearing as magenta.