The role of osmiophilic bodies and Pfg377 expression in female gametocyte emergence and mosquito infectivity in the human malaria parasite Plasmodium falciparum.
Osmiophilic bodies are membrane-bound vesicles, found predominantly in Plasmodium female gametocytes, that become progressively more abundant as the gametocyte reaches full maturity. These vesicles lie beneath the subpellicular membrane of the gametocyte, and the release of their contents into the parasitophorous vacuole has been postulated to aid in the escape of gametocytes from the erythrocyte after ingestion by the mosquito. Currently, the only protein known to be associated with osmiophilic bodies in Plasmodium falciparum is Pfg377, a gametocyte-specific protein expressed at the onset of osmiophilic body development. Here we show by targeted gene disruption that Pfg377 plays a fundamental role in the formation of these organelles, and that female gametocytes lacking the full complement of osmiophilic bodies are significantly less efficient both in vitro and in vivo in their emergence from the erythrocytes upon induction of gametogenesis, a process whose timing is critical for fertilization with the short-lived male gamete. This reduced efficiency of emergence explains the significant defect in oocyst formation in mosquitoes fed blood meals containing Pfg377-negative gametocytes, resulting in an almost complete blockade of infection.
de Koning-Ward
Tania F
TF
The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Vic. 3050, Australia.
Olivieri
Anna
A
Bertuccini
Lucia
L
Hood
Andrew
A
Silvestrini
Francesco
F
Charvalias
Konstantinos
K
Berzosa Díaz
Pedro
P
Camarda
Grazia
G
McElwain
Terry F
TF
Papenfuss
Tony
T
Healer
Julie
J
Baldassarri
Lucilla
L
Crabb
Brendan S
BS
Alano
Pietro
P
Ranford-Cartwright
Lisa C
LC
D000818:Animals; D009033:Culicidae / Q000469:parasitology*; D018274:Electroporation; D004912:Erythrocytes / Q000469:parasitology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005718:Gametogenesis; D005854:Germ Cells / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D015388:Organelles / Q000502:physiology; D010963:Plasmodium falciparum / Q000166:cytology* / Q000235:genetics / Q000472:pathogenicity*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*
D015800:Protozoan Proteins