Exploring the transcriptome of the malaria sporozoite stage.
Most studies of gene expression in Plasmodium have been concerned with asexual and/or sexual erythrocytic stages. Identification and cloning of genes expressed in the preerythrocytic stages lag far behind. We have constructed a high quality cDNA library of the Plasmodium sporozoite stage by using the rodent malaria parasite P. yoelii, an important model for malaria vaccine development. The technical obstacles associated with limited amounts of RNA material were overcome by PCR-amplifying the transcriptome before cloning. Contamination with mosquito RNA was negligible. Generation of 1,972 expressed sequence tags (EST) resulted in a total of 1,547 unique sequences, allowing insight into sporozoite gene expression. The circumsporozoite protein (CS) and the sporozoite surface protein 2 (SSP2) are well represented in the data set. A BLASTX search with all tags of the nonredundant protein database gave only 161 unique significant matches (P(N) < or = 10(-4)), whereas 1,386 of the unique sequences represented novel sporozoite-expressed genes. We identified ESTs for three proteins that may be involved in host cell invasion and documented their expression in sporozoites. These data should facilitate our understanding of the preerythrocytic Plasmodium life cycle stages and the development of preerythrocytic vaccines.
Kappe
S H
SH
Michael Heidelberger Division, Department of Pathology, Kaplan Cancer Center, New York University School of Medicine, New York, NY 10016, USA. kappes01@popmail.med.nyu.edu
Gardner
M J
MJ
Brown
S M
SM
Ross
J
J
Matuschewski
K
K
Ribeiro
J M
JM
Adams
J H
JH
Quackenbush
J
J
Cho
J
J
Carucci
D J
DJ
Hoffman
S L
SL
Nussenzweig
V
V
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000469:parasitology; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D006790:Host-Parasite Interactions / Q000235:genetics; D008024:Ligands; D017780:Malaria Vaccines; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics; D010967:Plasmodium yoelii / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D015800:Protozoan Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D016053:RNA, Protozoan / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics
D018076:DNA, Complementary; D008024:Ligands; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan