Levels of circumsporozoite protein in the Plasmodium oocyst determine sporozoite morphology.
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.
Thathy
Vandana
V
Department of Pathology, Michael Heidelberger Division of Immunology, New York University School of Medicine, New York, NY 10016, USA.
Fujioka
Hisashi
H
Gantt
Soren
S
Nussenzweig
Ruth
R
Nussenzweig
Victor
V
Ménard
Robert
R
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
D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan