A naturally occurring gene encoding the major surface antigen precursor p190 of Plasmodium falciparum lacks tripeptide repeats.
Plasmodium falciparum merozoites have variable surface proteins that are processed from a 190-kd precursor protein (p190). The gene encoding p190 exists in two allelic forms and cross-over events occurring mainly near the 5' end, combined with isolate-specific tripeptide repeats, contribute to its antigen diversity. We have sequenced a large portion of the p190 gene from the parasite isolate RO-33 (Ghana). Remarkably, the typical N-terminal tripeptide repeat structure is lacking. Apart from mutations in the variable parts, the gene appears identical to the MAD-20 allele (Papua, New Guinea). Southern blot analysis detects p190 genes similar to RO-33 in other parasite isolates independent of their geographical origin. The lack of p190 repeats in RO-33 eliminates the possibility that they are involved in host cell recognition or integration and restricts their function to immune escape.
Certa
U
U
Central Research Units, F. Hoffman-La Roche and Co. Ltd., Basel, Switzerland.
Rotmann
D
D
Matile
H
H
Reber-Liske
R
R
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics*; D001483:Base Sequence; D005796:Genes; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D010963:Plasmodium falciparum / Q000235:genetics*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics*
D000954:Antigens, Surface; D014643:Variant Surface Glycoproteins, Trypanosoma