Cloning and characterization of a new asparagine-rich protein in Plasmodium falciparum.
A cDNA clone that encodes a Plasmodium falciparum asparagine (N)-rich protein (PfARP) was isolated through immunoscreening of an expression library. A 9.4 kb PfARP transcript was identified by Northern blot hybridization and the gene was localized on chromosome 1. The complete coding sequence (6666 bp) revealed a protein that contains clustered as well as randomly distributed N residues (24.3%), seven copies of a repeat sequence [DNT(D/N)(K/N)(V/L/M)] and multiple copies of tripeptide repeats within a 101 amino acid region containing 89 D/E residues. The PfARP was immunogenic in inbred and outbred mice and endemic sera revealed the presence of low-titer antibodies against PfARP. Anti-PfARP sera showed cytoplasmic and surface localization of apparently cross-reactive malarial antigens in different life-cycle stages (ring, trophozoite, schizont, and gametocytes). Although the biological function(s) of PfARP are not known, the observation that it is present in multiple parasite stages and that it is a target of natural immune response warrants further study of PfARP as an immune target.
Zhang
K
K
Molecular Microbiology and Immunology, Johns Hopkins University School of Public Health, Baltimore, MD 21205, USA.
Fujioka
H
H
Lobo
C A
CA
Kitayaporn
D
D
Aikawa
M
M
Kumar
N
N
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003001:Cloning, Molecular; D003429:Cross Reactions; D018076:DNA, Complementary; D015723:Gene Library; D006801:Humans; D007114:Immunization; D015151:Immunoblotting; D007223:Infant; D016778:Malaria, Falciparum / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000254:growth & development* / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D017422:Sequence Analysis, DNA
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D018076:DNA, Complementary; C403009:PfARP protein, Plasmodium falciparum; D011994:Recombinant Proteins