title: The conserved plant sterility gene HAP2 functions after attachment of fusogenic membranes in Chlamydomonas and Plasmodium gametes.
abstract: The cellular and molecular mechanisms that underlie species-specific membrane fusion between male and female gametes remain largely unknown. Here, by use of gene discovery methods in the green alga Chlamydomonas, gene disruption in the rodent malaria parasite Plasmodium berghei, and distinctive features of fertilization in both organisms, we report discovery of a mechanism that accounts for a conserved protein required for gamete fusion. A screen for fusion mutants in Chlamydomonas identified a homolog of HAP2, an Arabidopsis sterility gene. Moreover, HAP2 disruption in Plasmodium blocked fertilization and thereby mosquito transmission of malaria. HAP2 localizes at the fusion site of Chlamydomonas minus gametes, yet Chlamydomonas minus and Plasmodium hap2 male gametes retain the ability, using other, species-limited proteins, to form tight prefusion membrane attachments with their respective gamete partners. Membrane dye experiments show that HAP2 is essential for membrane merger. Thus, in two distantly related eukaryotes, species-limited proteins govern access to a conserved protein essential for membrane fusion.
authors: Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors: Yanjie
authors: Y
authors: Liu
authors: Rita
authors: R
authors: Tewari
authors: Jue
authors: J
authors: Ning
authors: Andrew M
authors: AM
authors: Blagborough
authors: Sara
authors: S
authors: Garbom
authors: Jimin
authors: J
authors: Pei
authors: Nick V
authors: NV
authors: Grishin
authors: Robert E
authors: RE
authors: Steele
authors: Robert E
authors: RE
authors: Sinden
authors: William J
authors: WJ
authors: Snell
authors: Oliver
authors: O
authors: Billker
mesh_terms: D020418:Algal Proteins / Q000235:genetics*; D000818:Animals; D002696:Chlamydomonas / Q000235:genetics*; D005260:Female; D005854:Germ Cells / Q000502:physiology*; D008297:Male; D008561:Membrane Fusion / Q000235:genetics; D010962:Plasmodium berghei / Q000235:genetics*; D015800:Protozoan Proteins / Q000235:genetics*; D013084:Sperm-Ovum Interactions / Q000235:genetics*
chemical_list: D020418:Algal Proteins; D015800:Protozoan Proteins