Mutant/mutation
The mutant lacks expression of the P47 protein.

Protein (function)
The P47 protein is a member 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).

Phenotype
Phenotype analyses demonstrate that P47 plays an important role in fertilization (female fertility factor).  Motile males fail to attach to and penetrate female gametes lacking P47 (see phenotype description). P47 is specifically expressed on the surface of female gametocytes/gametes (no expression in male gametocytes/gametes). Mutant male gametes are fertile as has been shown by cross-fertilisation with wild type female gametes.

Additional information
This mutant is frequently used in cross-fertilization studies in which the fertile males are used to test the fertility of females of other mutants (Khan et al., Cell (2005) 121, 675-87; Raine, J.D. et al., PLoS Pathog (2007) 3,e30).

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.

P. falciparum mutants lacking expression of the female specific P47 (PF13_0248) produced oocyst numbers in Anopheles stephensi that were not different from wild type parasites (van Schaijk et al., 2006, Mol. Biochem. Parasitol. 149:216-22). 

The p47 gene forms a paralogous gene pair with the gene p48/45 that encodes P45/48 (PB001525.02.0 ; PF13_0247), which are closely linked in the genome.

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

Other mutants
RMgm-347: An independent mutant lacking expression of P47 and expresses GFP under the control of the constitutive eef1a promoter
RMgm-349: A mutant lacking expression of both P47 and P48/45