Inter-allelic recombination in the Plasmodium vivax merozoite surface protein 1 gene among Indian and Colombian isolates.
BACKGROUND
A major concern in malaria vaccine development is the polymorphism observed among different Plasmodium isolates in different geographical areas across the globe. The merozoite surface protein 1 (MSP-1) is a leading vaccine candidate antigen against asexual blood stages of malaria parasite. To date, little is known about the extent of sequence variation in the Plasmodium vivax MSP-1 gene (Pvmsp-1) among Indian isolates. Since P. vivax accounts for >50% of malaria cases in India and in Colombia, it is essential to know the Pvmsp-1 gene variability in these two countries to sustain it as a vaccine candidate. The extent of polymorphism in Pvmsp-1 gene among Indian and Colombian isolates is described.


METHODS
The sequence variation in the region encompassing the inter-species conserved blocks (ICBs) five and six of Pvmsp-1 gene was examined. PCR was carried out to amplify the polymorphic region of Pvmsp-1 and the PCR products from twenty (nine Indian and 11 Colombian) isolates were sequenced and aligned with Belem and Salvador-1 sequences.


RESULTS
Results revealed three distinct types of sequences among these isolates, namely, Salvador-like, Belem-like and a third type sequence which was generated due to interallelic recombination between Salvador-like sequences and Belem-like sequences. Existence of the third type in majority (44%) showed that allelic recombinations play an important role in PvMSP1 diversity in natural parasite population. Micro-heterogeneity was also seen in a few of these isolates due to nucleotide substitutions, insertions as well as deletions.


CONCLUSIONS
Intergenic recombination in the Pvmsp-1 gene was found and suggest that this is the main cause for genetic diversity of the Pvmsp-1 gene.
International Centre for Genetic Engineering and Biotechnology, New Delhi, India. amaestre@medicina.udea.edu.co
Amanda
A
Maestre
Sujatha
S
Sunil
Gul
G
Ahmad
Asif
A
Mohmmed
Marcela
M
Echeverri
Mauricio
M
Corredor
Silvia
S
Blair
Virander S
VS
Chauhan
Pawan
P
Malhotra
D000483:Alleles; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D003105:Colombia / Q000453:epidemiology; D017125:Genes, Protozoan / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D007194:India / Q000453:epidemiology; D016780:Malaria, Vivax / Q000453:epidemiology / Q000235:genetics; D020066:Merozoite Surface Protein 1 / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D010966:Plasmodium vivax / Q000145:classification / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic / Q000235:genetics; D015800:Protozoan Proteins / Q000737:chemistry / Q000145:classification / Q000235:genetics; D011995:Recombination, Genetic
D020066:Merozoite Surface Protein 1; D015800:Protozoan Proteins