Fig. 2. Clb2-GFP shows similar localization when expressed from its endogenous promoter. 15Du haploid cells in which two GFP tags were introduced in tandem at the CLB2 chromosomal locus were grown to midlog phase in YPD supplemented with 45 µg/ml adenine. Each frame was generated by projecting processed images (Hyugens software, Bitplane) of four focal planes taken at 0.15 µm intervals through the cell. Exposure times were 3 seconds for each plane, to be compared to a mean exposure time of 500 mseconds when the Clb2-GFP fusion is overexpressed.