Dataset Information

Diverse expression patterns of subgroups of the rif multigene family during Plasmodium falciparum gametocytogenesis.

ABSTRACT:

Background

The maturation of Plasmodium falciparum gametocytes in the human host takes several days, during which the parasites need to efficiently evade the host immune system. Like asexual stage parasites, immature gametocytes can sequester at various sites in the human body, and only mature sexual stages are found in the circulation. Although the fundamental mechanisms of gametocyte immune evasion are still largely unknown, candidate molecules that may be involved include variant antigens encoded by multigene families in the P. falciparum genome, such as the PfEMP1, STEVOR and RIFIN proteins. While expression of the former two families in sexual stages has been investigated earlier, we report here RIFIN expression during gametocytogenesis.

Methodology/principal findings

Variants of two previously characterized RIFIN subfamilies (A- and B-type RIFINs) were found to be synthesized in gametocytes. Immunofluorescence experiments showed A-type RIFINs to be accumulated in a crescent-shaped pattern of discrete punctate structures at the infected erythrocyte membrane, while members of the B-type family were associated with the parasite. Transcription analysis demonstrated the existence of diverse transcriptional regulation patterns during sexual differentiation and indicated variant-specific regulation of B-type RIFINs, in contrast to group-specific regulation for A-type RIFINs. Phylogenetic analysis of 5'-upstream regions showed that the rif-gene family falls into five defined clusters, designated rups (rifupstream) A1, A2, AB, B and C. In trophozoites and early gametocytes, rif variants of the rupsA2-type were preferentially expressed.

Conclusions/significance

In this work we demonstrate the expression dynamics of the rif-gene family during sexual differentiation and present indications for subgroup specific regulation patterns. Therefore, our data provide a first foundation and point to new directions for future investigations of the potential role of RIFINs in gametocyte immune evasion.

SUBMITTER: Petter M

PROVIDER: S-EPMC2582490 | biostudies-literature | 2008

REPOSITORIES: biostudies-literature

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Publications

Diverse expression patterns of subgroups of the rif multigene family during Plasmodium falciparum gametocytogenesis.

Petter Michaela M Bonow Insa I Klinkert Mo-Quen MQ

PloS one 20081120 11

<h4>Background</h4>The maturation of Plasmodium falciparum gametocytes in the human host takes several days, during which the parasites need to efficiently evade the host immune system. Like asexual stage parasites, immature gametocytes can sequester at various sites in the human body, and only mature sexual stages are found in the circulation. Although the fundamental mechanisms of gametocyte immune evasion are still largely unknown, candidate molecules that may be involved include variant anti ...[more]

PMID: 19020666

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Project description:BackgroundVariant antigens expressed on the surface of parasitized red blood cells (pRBCs) are important virulence factors of malaria parasites. Whereas Plasmodium falciparum erythrocyte membrane proteins 1 (PfEMP1) are responsible for sequestration of mature parasites, little is known about putative ligands mediating cytoadherence to host receptors in other Plasmodium species. Candidates include members of the pir superfamily found in the human parasite Plasmodium vivax (vir), in the simian pathogen Plasmodium knowlesi (kir) and in the rodent malarias Plasmodium yoelii (yir), Plasmodium berghei (bir) and Plasmodium chabaudi (cir). The aim of this study was to reveal a potential involvement of cir genes in P. chabaudi sequestration.MethodsSubfamilies of cir genes were identified by bioinformatic analyses of annotated sequence data in the Plasmodium Genome Database. In order to examine tissue-specific differences in the expression of cir mRNAs, RT-PCR with subfamily-specific primers was used. In total, 432 cDNA clones derived from six different tissues were sequenced to characterize the transcribed cir gene repertoire. To confirm differences in transcription profiles of cir genes, restriction fragment length polymorphism (RFLP) analyses were performed to compare different host tissues and to identify changes during the course of P. chabaudi infections in immunocompetent mice.ResultsThe phylogenetic analysis of annotated P. chabaudi putative CIR proteins identified two major subfamilies. Comparison of transcribed cir genes from six different tissues revealed significant differences in the frequency clones belonging to individual cir gene subgroups were obtained from different tissues. Further hints of difference in the transcription of cir genes in individual tissues were obtained by RFLP. Whereas only minimal changes in the transcription pattern of cir genes could be detected during the developmental cycle of the parasites, switching to expression of other cir genes during the course of an infection was observed around or after peak parasitemia.ConclusionsThe tissue-specific expression of cir mRNAs found in this study indicates correlation between expression of CIR antigens and distribution of parasites in inner organs. Together with comparable results for other members of the pir superfamily this suggests a role of cir and other pir genes in antigenic variation and sequestration of malaria parasites.

Dataset Information

Diverse expression patterns of subgroups of the rif multigene family during Plasmodium falciparum gametocytogenesis.

Background

Methodology/principal findings

Conclusions/significance

Publications

Diverse expression patterns of subgroups of the rif multigene family during Plasmodium falciparum gametocytogenesis.

Similar Datasets

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