Mutant/mutation
The mutant lacks expression of both P47 and P48/45.

Protein (function)
The P47 and P48/45 proteins are members of a small family of proteins, the 6-cysteine (cys) family of (surface) proteins. The proteins are characterized by domains of roughly 120 amino acids in size that contain six positionally conserved cysteines (6-cys). Although some species of Plasmodium (may) contain unique members of the 6-cys family, ten members have been identified that are conserved both in structure as well as in genome organization throughout the genus. Some of the conserved 6-cys proteins are encoded by genes that form paralogous gene-pairs which are closely linked in the genome separated by less then 2 kb of intergenic region. Most members have a GPI anchor and are predicted membrane surface proteins whereas others appear to be secreted and most members are expressed in a discrete stage-specific manner in gametocytes, sporozoites or merozoites (see also 'Additional Information'). P47 is specifically expressed on the surface of female gametocytes/gametes (no expression in male gametocytes/gametes) and P48/45 is expressed on the surface of both male and female gametocytes/gametes.

Phenotype
Phenotype analyses demonstrate that both P48/45 (male fertility factor) and  P47 (female fertility factor) play an important role in fertilization. See also mutants RMgm-15 and RMgm-348 that lack either P48/45 or P47. Motile males fail to attach to and penetrate female gametes (see phenotype description).

Additional information
The p47 gene forms a paralogous gene pair with the gene p48/45  which are closely linked in the genome. In this mutant the genes encoding P48/45 and P47 have been disrupted (double knock-out mutant) using a single DNA construct.

The mutant  shows very low levels of fertilization with higher fertilization rates in the mosquito than in in vitro ookinete cultures. Mutant parasites produce low numbers of ookinetes and oocysts in Anopheles stephensi mosquitoes (see also the phenotype description 'Fertilization and ookinete'). Both the ookinetes and oocysts show a normal morphology and oocysts produce normal numbers of sporozoites that are infectious to mice.

Table: P. falciparum gene members of the 6-cys family

Other mutants
RMgm-15: A mutant lacking expression of P48/45
RMgm-345: The mutant lacks expression of the P48/45 protein and expresses GFP under the control of a male specific promoter and RFP under the control of a female specific promoter. This mutant has been generated to be able to distinguish the female gametocytes/gametes and ookinetes based on their RFP expression in cross-fertilisation experiments with fertile males of other mutants and for determination of meiosis in cross-fertilisation studies. Meiosis in zygotes is determined by FACS analysis of the DNA content of Hoechst-stained gametes/zygotes selected based on their RFP-fluorescence.
RMgm-346: An independent mutant lacking expression of P48/45 which expresses GFP under the constitutive eef1a promoter. This mutant shows the same phenotype as other mutants lacking expression of P48/45. This mutant has been generated to be able to distinguish the female gametocytes and ookinetes based on their high GFP expression in cross-fertilisation experiments with fertile males of other mutants.
RMgm-347: A mutant lacking expression of P47 that expresses GFP under the constitutive eef1a promoter
RMgm-348: A mutant lacking expression of P47