Rapid activation of distinct member of multigene families in Plasmodium spp.
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PROVIDER: PRJNA526501 | ENA |
REPOSITORIES: ENA
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Project description:The objective of this study is to provide a novel method to study multigene proteins in Plasmodium spp. The method is based on selection linked integration (SLI), which allows positive selection of genomic integration events. By targeting specific members of multigene families, parasites are being selected for not only genomic integration but also expression of the targeted gene under its endogenous promoter
2019-03-12 | GSE128123 | GEO
Project description:Variant antigens that are encoded by large multigene families play an important role in the adaptation and immune evasion of a wide range of pathogens. However, the study of their biological function is significantly hampered by the difficulty in controlling their expression in its cellular setting. The genomes of Plasmodium spp. encode a number of different multigene families that are thought to play a critical role for their survival. However, with the exception of the P. falciparum var genes very little is known about the biological roles of any of the other multigene families. Here we report a highly efficient genetic system to study variant antigens in Plasmodium spp. using the Selection Linked Integration method; we are able to activate the expression of a single member of a multigene of our choice using its endogenous promoter.
2020-07-03 | GSE152162 | GEO
Project description:Rapid activation of distinct members of multigene families in Plasmodium spp.
| PRJNA638463 | ENA
Project description:RATIONALE: Developing a questionnaire that can be used to assess the quality of life among people who have a family member with cancer may help the study of cancer in the future.
PURPOSE: This clinical trial is studying quality of life among families with a member who is a cancer patient.
| 2045338 | ecrin-mdr-crc
Project description:PCR strategies for complete allele calling in multigene families using high-throughput sequencing approaches.
| PRJEB14070 | ENA
Project description:The genomes of Plasmodium spp. encode a number of different multigene families that are thought to play a critical role for survival. However, with the exception of the P. falciparum var genes, very little is known about the biological roles of any of the other multigene families. Using the recently developed Selection Linked Integration method, we have been able to activate the expression of a single member of a multigene family of our choice in Plasmodium spp. from its endogenous promoter. We demonstrate the usefulness of this approach by activating the expression of a unique var, rifin and stevor in P. falciparum as well as yir in P. yoelii. Characterization of the selected parasites reveals differences between the different families in terms of mutual exclusive control, co-regulation, and host adaptation. Our results further support the application of the approach for the study of multigene families in Plasmodium and other organisms.
| S-EPMC7334209 | biostudies-literature
Project description:The process of erythrocyte invasion by merozoites of Plasmodium falciparum involves multiple steps, including the formation of a moving junction characterized by the redundancy of many of the receptor-ligand interactions involved. Several of the parasite proteins that interact with erythrocyte receptors or participate in other steps of the process of invasion are encoded by small subtelomerically-located multigene families of four to seven members. We report here that members of the multigene families pfRh, eba, rhopH1/clag and acbp exist in either an active or a silenced state. In the case of two members of the rhopH1/clag family, clag3.1 and clag3.2, expression was mutually exclusive. Silencing occurred in the absence of detectable DNA alterations, suggesting that it is transmitted epigenetically. This was unambiguously demonstrated for eba-140, which was silenced by the formation of facultative heterochromatin. Our data demonstrate that variant expression, epigenetic silencing and mutually exclusive expression in Plasmodium are not unique to genes encoding proteins exported to the surface of the erythrocyte like var genes but also occur for genes involved in host cell invasion..
2007-11-26 | E-SGRP-9 | biostudies-arrayexpress
Project description:The P. falciparum genome is equipped with several subtelomeric gene families that are implicated in parasite virulence and immune evasion. The members of these gene families are uniformly positioned within heterochromatic domains of the genome and are thus subject to variegated expression. The best-studied example is that of the var gene family encoding the major parasite virulence factor P. falciparum erythrocyte membrane protein 1 (PfEMP1). Transcriptional regulation of other subtelomeric gene families and their role in parasite biology is much less understood. Here, we investigated the mode of transcriptional control of var, rif, stevor, phist and pfmc-2tm families by comparative genome-wide transcriptional profiling of transgenic parasite lines. Our results establish a clear functional distinction between var and non-var transcriptional control mechanisms. Unlike var promoters, we find that promoters of non-var families are not silenced by default. Moreover, we show that mutually exclusive transcription is unique to the var gene family. 3D7 wild-type parasites were transfected with constructs carrying eight different promoters that drive expression of the drug-selectable marker hdhfr-gfp. Thereof seven promoters are members of the multigene families upsA var, upsB var, upsC var, rif, stevor, phistb and pfmc-2tm. The cam promoter was used as transfection-based control and also a wild-type 3D7 cell line was included as control. These nine cell lines were subjected to genome-wide transcriptional profiling. Parasites were synchronized to obtain an 8 hour growth window and were harvested at four consecutive timepoints (TP): TP1 (6-14 hours post-invasion (hpi)); TP2 (14-22 hpi); TP3 (22-30 hpi); TP4 (30-38 hpi) to monitor intra- and inter-family specific linkage of multigene family expression.
2011-09-01 | E-GEOD-31829 | biostudies-arrayexpress
Project description:Plasmodium multigene families are thought to play important roles in the pathogenesis of malaria. Plasmodium interspersed repeat (pir) genes comprise the largest multigene family in many Plasmodium species. However, their expression pattern and localisation remain to be elucidated. Protein subcellular localisation is fundamental to be able to elucidate the functional importance and cell-cell interactions of the PIR proteins. Here, we use the rodent malaria parasite, Plasmodium chabaudi chabaudi, as a model to investigate the localisation pattern of this gene family. We found that most PIR proteins are co-expressed in clusters during acute and chronic infection; members of the S7 clade are predominantly expressed during the acute-phase, whereas members of the L1 clade dominate the chronic-phase of infection. Using peptide antisera specific for S7 or L1 PIRS, we show that S7 and L1 PIRs have different localisations within the infected red blood cells. S7 PIRs are exported into the infected red blood cells cytoplasm where they are co-localised with parasite-induced host cell modifications termed Maurer's clefts, whereas L1 PIRs are localised on or close to the parasitophorous vacuolar membrane. This localisation pattern changes following mosquito transmission and during progression from acute- to chronic-phase of infection. However, neither S7 nor L1 PIR proteins detected by the peptide antisera are localised on the surface of infected red blood cells, suggesting that they are unlikely to be targets of surface variant-specific antibodies or be involved directly in adhesion of infected red blood cells to host cells, as described for Plasmodium falciparum VAR proteins. Their presence on Maurer’s clefts, as seen for Plasmodium falciparum RIFIN and STEVOR proteins, might further suggest trafficking of the PIRs on the surface of the infected erythrocytes. The differences in subcellular localisation of the two major clades of Plasmodium chabaudi PIRs across the blood cycle, and the apparent lack of expression on the red cell surface strongly suggest that the function(s) of this gene family may differ from those of other multigene families of Plasmodium, such as the var genes of Plasmodium falciparum.
2022-06-14 | PXD031586 | Pride