Pb103 Regulates Zygote/Ookinete Development in Plasmodium berghei via Double Zinc Finger Domains

• Published in: Pathogens (Basel) Vol. 10; no. 12; p. 1536
• Main Authors: Hirai, Makoto, Maeta, Akimasa, Mori, Toshiyuki, Mita, Toshihiro
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.11.2021; MDPI
• Subjects: Aquatic insects; Assaying; Cross-fertilization; Culicidae; Females; Fluorescence; Gametes; Gametocytes; Gene expression; Green fluorescent protein; In vitro fertilization; Malaria; Males; Mosquitoes; mRNA; Oocysts; Parasites; Parasitic diseases; Plasmodium berghei; Proteins; Reproduction (biology); RNA binding protein; Roles; Sexual reproduction; Translation; translational repression; Zinc; zinc finger; Zinc finger proteins; Zygotes; Plasmodium berghei; translational repression; zinc finger; RNA binding protein
• ISSN: 2076-0817; 2076-0817
• DOI: 10.3390/pathogens10121536

Sexual reproduction of parasites takes place in anopheline mosquitoes, where male and female gametes fuse to form zygotes and then ookinetes. These processes are orchestrated by stage-specific protein expression, which is mediated in part by translational repression. Accumulating evidence shows that RNA binding proteins (RBPs) play crucial roles in these processes. Here, we report the characterization of 103 (Pb103), which encodes a protein possessing double zinc finger domains (ZFs), an RBP. Reporter parasites expressing azami green fluorescent protein (AGFP) under the endogenous gene promoter ( reporter) showed that the AGFP fluorescent signal was detected from gametes to ookinetes, while mRNA was translationally repressed in female gametocytes. The -disrupted parasites ( ) grew and produced gametocytes with similar efficiencies to those of wild-type parasites. However, no oocysts were formed in mosquitoes fed . An in vitro fertilization assay showed abortion at the zygote stage in , suggesting that Pb103 plays a critical role in zygote/ookinete development. Cross-fertilization assays with and male- or female-sterile parasites revealed that Pb103 was essential exclusively for female gametes. To identify the domains critical for zygote/ookinete development, transgenic parasites expressing partially deleted Pb103 were generated and assayed for ookinete maturation. As a result, deleting either of two ZFs but not the C-terminal region abolished zygote/ookinete development, highlighting the indispensable roles of ZFs in parasite sexual development, most likely via translational repression.