Regulators of male and female sexual development critical for transmission of a malaria parasite

Abstract

The transmission of malaria parasites from vertebrate host to mosquito vector requires a developmental switch in asexually dividing blood-stage parasites to sexual reproduction. In Plasmodium berghei the transcription factor AP2-G is required and sufficient for this switch, but how a particular sex is determined in a haploid parasite remains unknown. Using a global screen of barcoded mutants, we here identify ten genes essential for the formation of either male or female sexual forms and validate their importance for transmission. High-resolution single-cell transcriptomics of wild-type and mutant parasites portrays the developmental bifurcation and reveals a regulatory cascade of putative gene functions in determination and subsequent differentiation of each sex. A male-determining gene with a LOTUS/OST-HTH domain points towards unexpected conservation of molecular mechanisms of gametogenesis in animals and a distantly related eukaryotic parasite.

Pf ARID Regulates P. falciparum Malaria Parasite Male Gametogenesis and Female Fertility and Is Critical for Parasite Transmission to the Mosquito Vector

“…Downregulation of the ZFPs suggested that Pf ARID functions upstream of ZFPs and that it might have a regulatory role for expression of these genes during gametogenesis and beyond. This hypothesis is also supported by the recent functional studies in the rodent malaria parasite P. berghei , where female development 4 (FD4) (an ortholog of PF3D7_1220000) is important for completion of female-specific development ( 42 ). An additional two ZFPs, PBANKA_1357900 (PF3D7_1345000 ortholog) and PBANKA_0608600 (PF3D7_1210200 ortholog) are critical for the blood to midgut oocyst transition ( 43 ), suggesting roles in sexual-stage development.…”

“…The Pfarid – genetic crosses we performed with transgenic lines producing either fertile microgametes ( 6 ) or macrogametes ( 35 ) confirmed a completely penetrant male defect but, surprisingly, also showed that Pf ARID is required for fertility of female gametes. A recent study describing screening for fertility-related genes in the rodent malaria parasite P. berghei , showed that the P. berghei ARID ( Pb ARID) ortholog named MD4 (PBANKA_0102400) is involved in fertility of male gametes only ( 42 ). Thus, ARID might differ in its sex-specific functions among different malaria parasite species.…”

Gene-by-gene screen of the unknown proteins encoded onP. falciparumchromosome 3

“…To assign this on a large scale, genome-wide approaches have been carried out in P. berghei , and P. falciparum parasites (Bushell et al, 2017; Zhang et al, 2018). These approaches also permit functional and stage specific screens (Russell et al, 2021; Stanway et al, 2019; Thomas et al, 2016). However, they provide no data for the cellular location of individual proteins nor cell lines for their functional analysis.…”

CRISPR/Cas9 and genetic screens in malaria parasites: small genomes, big impact

“…Pools of barcoded mutants were generated in a fluorescent reporter line with green male and red female gametocytes, facilitating the combination of fluorescence-activated cell sorting (FACS) with BarSeq to identify mutants failing to generate male, female or both sex gametocytes. This study pinpointed 30 genes required for the formation of both male and female gametocytes, and 21 genes required exclusively for female and 14 for male gametocytogenesis including regulators expressed very early in sexual development (preprint, [ 35 ]).…”