Interchromosomal exchange of a large subtelomeric segment in a Plasmodium falciparum cross.

Abstract

Duplications and interchromosomal transpositions of chromosome segments are implicated in the genetic variability of Plasmodium falciparum malaria parasites. One parasite clone, HB3, was shown to lack a subtelomeric region of chromosome 13 that normally carries a PfHRPIII gene. We show here that the chromosome 13 segment carrying PfHRPIII was replaced in HB3 by a duplicated terminal segment from chromosome 11. Mapping results indicate that the segment includes at least 100‐200 kb of subtelomeric DNA and contains duplicated copies of the Pf332 and RESA‐2 genes. We followed inheritance of this duplication in a genetic cross between the HB3 and another P.falciparum clone, Dd2, that is euploid for the Pf332, RESA‐2 and PfHRPIII genes. Three types of progeny from the cross showed expected inheritance forms: a Dd2 euploid parent type, an HB3 aneuploid parent type, and a recombinant euploid type that carried PfHRPIII from Dd2 chromosome 13 and Pf332 from HB3 chromosome 11. However, a fourth euploid progeny type was also observed, in which the chromosome 13 segment from HB3 was transposed back to replace the terminus of chromosome 11. Three of 14 individual progeny were of this type. These findings suggest a mechanism of recombination from subtelomeric pairing and exchange between non‐homologous chromosomes in meiosis.

Expression of var Genes Located within Polymorphic Subtelomeric Domains of Plasmodium falciparum Chromosomes

“…The subtelomeric domains of P. falciparum chromosomes are characterized by arrays of repetitive sequence elements (11,27), which are believed to facilitate ectopic recombination between heterologous chromosomes (9,19). Such ectopic recombination events are known to occur in P. falciparum, are meiotically and mitotically stable, and render chromosome ends hot spots of recombination (16,43).…”

Export of virulence proteins by malaria-infected erythrocytes involves remodeling of host actin cytoskeleton

“…In contrast, the MC resident protein SBP1 ( Figure 3C), REX1 ( Figure 3D), MAHRP 1, and Pf332, which are PNEP exported proteins (supplemental Figure 1D), 48 are exported into the RBC cytoplasm but their localization was different to CS2. These proteins localize to small puncta within the RBC cytoplasm of CS2ΔPTP1-infected cells instead of MC in the parental line.…”

Gene targeting demonstrates that thePlasmodium bergheisubtilisin PbSUB2 is essential for red cell invasion and reveals spontaneous genetic recombination events

“…Such genetic rearrangements might be favoured by quick and repetitive Plasmodium mitoses (i.e. schizogony) as proposed previously for locus duplication, chromosome breakage and subtelomeric exchange (Hinterberg et al, 1994;Janse et al, 1994). The cloned SUB2-KI recombinant parasite population was heterogeneous after genomic rearrangements, illustrating the loss of clonality during the intraerythrocytic cycle.…”