title: Levels of circumsporozoite protein in the Plasmodium oocyst determine sporozoite morphology.
abstract: The sporozoite stage of the Plasmodium parasite is formed by budding from a multinucleate oocyst in the mosquito midgut. During their life, sporozoites must infect the salivary glands of the mosquito vector and the liver of the mammalian host; both events depend on the major sporozoite surface protein, the circumsporozoite protein (CS). We previously reported that Plasmodium berghei oocysts in which the CS gene is inactivated do not form sporozoites. Here, we analyzed the ultrastructure of P.berghei oocyst differentiation in the wild type, recombinants that do not produce or produce reduced amounts of CS, and corresponding complemented clones. The results indicate that CS is essential for establishing polarity in the oocyst. The amounts of CS protein correlate with the extent of development of the inner membranes and associated microtubules underneath the oocyst outer membrane, which normally demarcate focal budding sites. This is a first example of a protein controlling both morphogenesis and infectivity of a parasite stage.
authors.affiliation: Department of Pathology, Michael Heidelberger Division of Immunology, New York University School of Medicine, New York, NY 10016, USA.
authors.forename: Vandana
authors.initials: V
authors.lastname: Thathy
authors.forename: Hisashi
authors.initials: H
authors.lastname: Fujioka
authors.forename: Soren
authors.initials: S
authors.lastname: Gantt
authors.forename: Ruth
authors.initials: R
authors.lastname: Nussenzweig
authors.forename: Victor
authors.initials: V
authors.lastname: Nussenzweig
authors.forename: Robert
authors.initials: R
authors.lastname: Ménard
mesh_terms: D000818:Animals; D000852:Anopheles; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D009024:Morphogenesis; D016296:Mutagenesis; D010641:Phenotype; D010962:Plasmodium berghei / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D015800:Protozoan Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan