PF3D7_0729700

PF3D7_0729700 is a zinc-finger protein that functions as a female-determining factor in Plasmodium berghei sexual development, controlling female gametocyte determination and differentiation (PMID:36634679). Its identified protein interactors place it within germ-granule-like ribonucleoprotein complexes that act to complement transcriptional processes during female gametocyte commitment (PMID:36634679). Consistent with an RNA-associated role, the P. falciparum protein rescues the polyA+ mRNA nuclear export defect and proliferation arrest caused by depletion of its Toxoplasma gondii homolog TgZNF2, indicating that an mRNA nuclear export activity of this zinc-finger protein is conserved in P. falciparum (PMID:27385072). Beyond its assignment as a female-determining factor operating through ribonucleoprotein complexes (PMID:36634679) and this cross-species complementation of mRNA export (PMID:27385072), no further mechanistic detail on PF3D7_0729700 has been characterized in the available corpus.

1. 2016 Low

   Whether the RNA-handling function of the Toxoplasma zinc-finger protein TgZNF2 was shared by a Plasmodium counterpart was unknown; heterologous complementation established that the P. falciparum homolog PF3D7_0729700 can substitute for TgZNF2 in mRNA nuclear export.

   Evidence Complementation of an inducible T. gondii TgZNF2 knockout (iKO-TgZNF2) with the full-length P. falciparum homolog and a polyA+ mRNA localization assay

   PMID:27385072

   Open questions at the time

   • Function inferred in a heterologous T. gondii system, not directly demonstrated in P. falciparum
   • No direct assay of mRNA export by PF3D7_0729700 in P. falciparum cells
   • RNA targets and mechanism of export activity not defined
2. 2023 Medium

   The role of PF3D7_0729700 in the parasite's own biology was unknown; a functional-genetic and transcriptomic screen defined it as a female-determining factor acting through germ-granule-like ribonucleoprotein complexes in sexual development.

   Evidence Global screen of barcoded mutants with high-resolution single-cell transcriptomics of mutant parasites and identification of protein interactors, in P. falciparum

   PMID:36634679

   Open questions at the time

   • Single lab, though two orthogonal approaches
   • Molecular mechanism linking the zinc-finger protein to female commitment not resolved
   • Direct RNA substrates within the germ-granule-like complexes not identified

• It remains unresolved whether the conserved mRNA nuclear export activity inferred from Toxoplasma complementation is the mechanistic basis of the female-determining role in P. falciparum, and what RNA targets the protein acts on.
• No direct demonstration of mRNA export by PF3D7_0729700 in P. falciparum
• No structural or domain-level mechanism reported
• Composition and RNA cargo of the germ-granule-like ribonucleoprotein complexes not defined