Sex-Specific Biology of the Human Malaria Parasite Revealed from the Proteomes of Mature Male and Female Gametocytes

Abstract

The gametocytes of the malaria parasites are obligate for perpetuating the parasite's life cycle through mosquitoes, but the sex-specific biology of gametocytes is poorly understood. We generated a transgenic line in the human malaria parasite Plasmodium falciparum, which allowed us to accurately separate male and female gametocytes by flow cytometry. In-depth analysis of the proteomes by liquid chromatography-tandem mass spectrometry identified 1244 and 1387 proteins in mature male and female gametocytes, respectively. GFP-tagging of nine selected proteins confirmed their sex-partitions to be agreeable with the results from the proteomic analysis. The sexspecific proteomes showed significant differences that are consistent with the divergent functions of the two sexes. Although the male-specific proteome (119 proteins) is enriched in proteins associated with the flagella and genome replication, the female-specific proteome (262 proteins) is more abundant in proteins involved in metabolism, translation and organellar functions. Compared with the Plasmodium berghei sex-specific proteomes, this study revealed both extensive conservation and considerable divergence between these two species, which reflect the disparities between the two species in proteins involved in cytoskeleton, lipid metabolism and protein degradation. Comparison with three sex-specific proteomes allowed us to obtain high-confidence lists of 73 and 89 core male-and female-specific/biased proteins conserved in Plasmodium. The identification of sex-specific/biased proteomes in Plasmodium lays a solid foundation for understanding the molecular mechanisms underlying the unique sex-specific biology in this earlybranching eukaryote. Molecular & Cellular Proteomics

Comparative transcriptomics of female and male gametocytes in Plasmodium berghei and the evolution of sex in alveolates

“…Three proteomic studies on separated female and male gametocytes have been published, one in P. berghei [ 8 ] and two in P. falciparum [ 12 , 13 ]. Two of these studies compared female and male gametocytes to the precursor asexual stages, allowing identification of female- and male-upregulated proteins [ 8 , 12 ]. There has been one previous transcriptomic analysis on separated female and male gametocytes, in P. falciparum , where proteomic data was also generated [ 13 ].…”

Probabilistic data integration identifies reliable gametocyte-specific proteins and transcripts in malaria parasites

“…We further identify a number of proteins as gametocyte- specific even though they had been reported as asexual by previous studies (Fig 4B). A recent proteomics study of male and female Pf gametocytes [33], not included in our original analysis, was used to test the robustness of our scores. When we included this data set in our final Bayesian proteomics scores, both gametocyte scores and gene ranks before and after addition of this data set were highly correlated (Pearson’s r=0.997 and Spearman’s rho=0.995, respectively).…”

“…Our approach suggests that the currently available MS data is sufficiently comprehensive to identify stage specific proteins when analysed in an integrative approach. We examined this directly by incorporating a new Pf gametocyte MS study [33] in our scoring. The authors reported 44 new gametocyte-specific proteins that were not reported by earlier studies.…”

Characterization of Plasmodium berghei Pbg37 as Both a Pre- and Postfertilization Antigen with Transmission-Blocking Potential

“…The availability of the proteomic data from the gametocyte stage to the ookinete stage provides unprecedented opportunities for TBV antigen discovery (31)(32)(33)(34). In silico screening of TBV candidates using filters for potential surface localization and exclusive expression in sexual stages may yield very useful results worthy of future pursuance (35).…”