Figure 1.

Identification and deletion of the fission yeast Spp1. (A) Alignment of the amino acid sequence of fission yeast Spp1 with the homologous proteins from human, M. musculus (mouse), D. melanogaster (Dm), and S. cerevisiae (Sc). Sequences and residues that are identical to Spp1 are shaded in black. (B) Deletion of the open reading frame (ORF) of spp1⁺ was achieved by replacing the ClaI-ClaI fragment that contains the majority of the ORF with the ura4⁺ gene. S, SalI; C, ClaI; H, HindIII; X, XbaI. This linear construct was transformed into a wild-type h⁺/h⁻ diploid, and uracil prototrophs were selected. (C) FACS analysis of germinating spores arising from either spp1⁻/spp1⁺ (right) or spp1⁺/spp1⁺ (left) diploids. Time points were taken hourly after the inoculation of spores in minimal media containing nitrogen, but lacking uracil. (D) Morphology of either spp1⁺ (left) or spp1⁻ (right) cells 18 h after germination in nitrogen-containing media lacking uracil. Cells displaying the “cut” phenotype are indicated with an arrow.