Figure 6.

GEX1 is in the nuclear envelope in Chlamydomonas and Plasmodium. (A) Immunoblots of total cellular protein (whole cells) and the nuclear and cytoplasmic/membrane fractions prepared from minus gametes expressing a Flag-tagged GEX1 protein. CALK and FMG are cytoplasmic and flagellar/membrane proteins, respectively, and histone 3 (H3) is a nuclear protein. Equal amounts of protein were loaded in each lane. (B) Confocal immunofluorescence microscopy of wild-type and gex1/GEX1-Flag-expressing gametes stained with anti-Flag antibody and the DNA dye DRAQ5. Bar, 10 μm. (C) Anti-Flag immunostaining of zygotes fixed ∼20 min after fusion of wild-type plus gametes with gex1/GEX1-Flag minus gametes. GEX1-Flag can be detected in both nuclei. Bar, 10 μm. (D) Confocal immunofluorescence analysis of P. berghei sexual stages expressing a C-terminally HA epitope-tagged protein from the endogenous gex1 locus. Gametocytes were from peripheral blood. To distinguish sexes, fixed gametocytes were immunolabeled for α-tubulin (expressed highly in males) and GFP (expressed more highly from the eef1αa promoter in females). Bar, 2 μm.