Fig. 1.

DIE5 is a developmentally regulated gene encoding a nuclear protein in Paramecium. (A) Northern blot of total RNA (20 μg per lane) from Paramecium probed with Paramecium DIE5a. Ethidium bromide staining of rRNA was used as a loading control. (B) Cellular localization of GFP-Die5a expressed from an extrachromosomal DNA driven by the DIE5a promoter. Fluorescent images are projections of optical sections obtained by confocal microscopy. The GFP fluorescence exclusively localized to the new macronuclei, which show weaker propidium iodide staining (DNA) than the old macronuclear fragments. The image corresponds to a cell approximately 14 h after the start of mating. The bar corresponds to 20 μm.