Sequence diversity and antigenic polymorphism in the Plasmodium yoelii p235 high molecular mass rhoptry proteins and their genes.
A gene family in Plasmodium yoelii YM encodes p235, a group of high molecular mass erythrocyte-binding rhoptry proteins. Sequence analysis of 6 cDNA clones from the 3' end of expressed p235 genes divided them into two groups corresponding to genes on chromosomes 1, and 5 and 6, respectively. Twelve partial p235 protein sequences, derived from cDNA sequences from the region with greatest protein sequence similarity to Plasmodium vivax RBP2, fell into three groups, together with one chimeric sequence. A comparison of these cDNA sequences with genomic DNA sequences from the same region suggested that only a subset of the gene repertoire is expressed. Three genomic DNA clones, derived from the 5' end of p235 genes designated E1, E2, and E5 and located on chromosome 5/6, were also obtained and aligned with sequences from the known E8 and E3 genes. In the region of overlap there was only approximately 27% protein sequence identity, indicating that the sequences in this p235 N-terminal region are more diverse than at the C-terminal end. This sequence variation in the expressed genes did not result in antigenically different rhoptry proteins as detected with a panel of p235-specific mAbs. Only one schizont out of 500 examined with mAb 25.86 appeared to be an antigenic variant, with all of the developing merozoites in this schizont being mAb 25.86 negative. No other antigenic variants were detected with the other antibodies, and therefore it is likely that these antibodies recognise conserved epitopes.
Narum
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DL
Division of Parasitology, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
Green
J L
JL
Ogun
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SA
Holder
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AA
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000276:immunology; D000918:Antibody Specificity; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D005091:Exons / Q000235:genetics; D005455:Fluorescent Antibody Technique; D014644:Genetic Variation / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation / Q000235:genetics; D010967:Plasmodium yoelii / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D011110:Polymorphism, Genetic / Q000235:genetics*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C065352:rhoptry associated protein, Plasmodium