Limits...
Targeted disruption of py235ebp-1: invasion of erythrocytes by Plasmodium yoelii using an alternative Py235 erythrocyte binding protein.

Ogun SA, Tewari R, Otto TD, Howell SA, Knuepfer E, Cunningham DA, Xu Z, Pain A, Holder AA - PLoS Pathog. (2011)

Bottom Line: The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family.In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another.We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression.

View Article: PubMed Central - PubMed

Affiliation: Division of Parasitology, MRC National Institute for Medical Research, London, UK. sogun@nimr.mrc.ac.uk

ABSTRACT
Plasmodium yoelii YM asexual blood stage parasites express multiple members of the py235 gene family, part of the super-family of genes including those coding for Plasmodium vivax reticulocyte binding proteins and Plasmodium falciparum RH proteins. We previously identified a Py235 erythrocyte binding protein (Py235EBP-1, encoded by the PY01365 gene) that is recognized by protective mAb 25.77. Proteins recognized by a second protective mAb 25.37 have been identified by mass spectrometry and are encoded by two genes, PY01185 and PY05995/PY03534. We deleted the PY01365 gene and examined the phenotype. The expression of the members of the py235 family in both the WT and gene deletion parasites was measured by quantitative RT-PCR and RNA-Seq. py235ebp-1 expression was undetectable in the knockout parasite, but transcription of other members of the family was essentially unaffected. The knockout parasites continued to react with mAb 25.77; and the 25.77-binding proteins in these parasites were the PY01185 and PY05995/PY03534 products. The PY01185 product was also identified as erythrocyte binding. There was no clear change in erythrocyte invasion profile suggesting that the PY01185 gene product (designated PY235EBP-2) is able to fulfill the role of EBP-1 by serving as an invasion ligand although the molecular details of its interaction with erythrocytes have not been examined. The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family. In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another. We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression.

Show MeSH

Related in: MedlinePlus

Parasite growth in vivo.The course of parasite growth was monitored in groups of 5 Balb/c mice                            infected intravenously (i.v.) on day 0 with 200, 1000, or 5000 WT or                            PY01365-KO parasitized erythrocytes. A Giemsa-stained blood smear from                            each mouse was made daily from day 3, the parasitaemia was counted and                            used to monitor the course of infection up to day 6. Error bars are                            standard error of mean (SEM). The bars are: 200 KO (vertical patterned),                            200 WT (light gray), 1000 KO (horizontal patterned), 1000 WT (dark                            gray), 5000 KO (white), and 5000 WT (black).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3040676&req=5

ppat-1001288-g008: Parasite growth in vivo.The course of parasite growth was monitored in groups of 5 Balb/c mice infected intravenously (i.v.) on day 0 with 200, 1000, or 5000 WT or PY01365-KO parasitized erythrocytes. A Giemsa-stained blood smear from each mouse was made daily from day 3, the parasitaemia was counted and used to monitor the course of infection up to day 6. Error bars are standard error of mean (SEM). The bars are: 200 KO (vertical patterned), 200 WT (light gray), 1000 KO (horizontal patterned), 1000 WT (dark gray), 5000 KO (white), and 5000 WT (black).

Mentions: To evaluate the phenotypic effect of deleting py235ebp-1 from the genome of the virulent P. yoelii YM line, for example on the age of the host cell invaded or on the course of infection, groups of 5 mice were injected with parasitized erythrocytes. P. yoelii parasites of the KO line showed no changed preference for a particular host cell type relative to WT parasites. All host cell types, both mature erythrocytes and reticulocytes, were invaded, indicating that deletion of the PY01365 gene (py235ebp-1) did not restrict the parasites to invasion of reticulocytes. In mice made reticulocytemic there was no difference in cell preference or growth rate between the two parasite lines (data not shown). Parasite growth kinetics for all groups of mice were very similar and there was no clear difference in the parasite multiplication rate (Figure 8). Only in the group injected with a thousand parasitized erythrocytes was there a significant reduction in parasite growth, when comparing the KO and WT parasite lines (P<0.05). Disruption of the PY01365 gene was not lethal to the parasite and no phenotype was detectable with respect to the age of host cell invaded.


Targeted disruption of py235ebp-1: invasion of erythrocytes by Plasmodium yoelii using an alternative Py235 erythrocyte binding protein.

Ogun SA, Tewari R, Otto TD, Howell SA, Knuepfer E, Cunningham DA, Xu Z, Pain A, Holder AA - PLoS Pathog. (2011)

Parasite growth in vivo.The course of parasite growth was monitored in groups of 5 Balb/c mice                            infected intravenously (i.v.) on day 0 with 200, 1000, or 5000 WT or                            PY01365-KO parasitized erythrocytes. A Giemsa-stained blood smear from                            each mouse was made daily from day 3, the parasitaemia was counted and                            used to monitor the course of infection up to day 6. Error bars are                            standard error of mean (SEM). The bars are: 200 KO (vertical patterned),                            200 WT (light gray), 1000 KO (horizontal patterned), 1000 WT (dark                            gray), 5000 KO (white), and 5000 WT (black).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3040676&req=5

ppat-1001288-g008: Parasite growth in vivo.The course of parasite growth was monitored in groups of 5 Balb/c mice infected intravenously (i.v.) on day 0 with 200, 1000, or 5000 WT or PY01365-KO parasitized erythrocytes. A Giemsa-stained blood smear from each mouse was made daily from day 3, the parasitaemia was counted and used to monitor the course of infection up to day 6. Error bars are standard error of mean (SEM). The bars are: 200 KO (vertical patterned), 200 WT (light gray), 1000 KO (horizontal patterned), 1000 WT (dark gray), 5000 KO (white), and 5000 WT (black).
Mentions: To evaluate the phenotypic effect of deleting py235ebp-1 from the genome of the virulent P. yoelii YM line, for example on the age of the host cell invaded or on the course of infection, groups of 5 mice were injected with parasitized erythrocytes. P. yoelii parasites of the KO line showed no changed preference for a particular host cell type relative to WT parasites. All host cell types, both mature erythrocytes and reticulocytes, were invaded, indicating that deletion of the PY01365 gene (py235ebp-1) did not restrict the parasites to invasion of reticulocytes. In mice made reticulocytemic there was no difference in cell preference or growth rate between the two parasite lines (data not shown). Parasite growth kinetics for all groups of mice were very similar and there was no clear difference in the parasite multiplication rate (Figure 8). Only in the group injected with a thousand parasitized erythrocytes was there a significant reduction in parasite growth, when comparing the KO and WT parasite lines (P<0.05). Disruption of the PY01365 gene was not lethal to the parasite and no phenotype was detectable with respect to the age of host cell invaded.

Bottom Line: The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family.In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another.We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression.

View Article: PubMed Central - PubMed

Affiliation: Division of Parasitology, MRC National Institute for Medical Research, London, UK. sogun@nimr.mrc.ac.uk

ABSTRACT
Plasmodium yoelii YM asexual blood stage parasites express multiple members of the py235 gene family, part of the super-family of genes including those coding for Plasmodium vivax reticulocyte binding proteins and Plasmodium falciparum RH proteins. We previously identified a Py235 erythrocyte binding protein (Py235EBP-1, encoded by the PY01365 gene) that is recognized by protective mAb 25.77. Proteins recognized by a second protective mAb 25.37 have been identified by mass spectrometry and are encoded by two genes, PY01185 and PY05995/PY03534. We deleted the PY01365 gene and examined the phenotype. The expression of the members of the py235 family in both the WT and gene deletion parasites was measured by quantitative RT-PCR and RNA-Seq. py235ebp-1 expression was undetectable in the knockout parasite, but transcription of other members of the family was essentially unaffected. The knockout parasites continued to react with mAb 25.77; and the 25.77-binding proteins in these parasites were the PY01185 and PY05995/PY03534 products. The PY01185 product was also identified as erythrocyte binding. There was no clear change in erythrocyte invasion profile suggesting that the PY01185 gene product (designated PY235EBP-2) is able to fulfill the role of EBP-1 by serving as an invasion ligand although the molecular details of its interaction with erythrocytes have not been examined. The PY01365, PY01185, and PY05995/PY03534 genes are part of a distinct subset of the py235 family. In P. falciparum, the RH protein genes are under epigenetic control and expression correlates with binding to distinct erythrocyte receptors and specific invasion pathways, whereas in P. yoelii YM all the genes are expressed and deletion of one does not result in upregulation of another. We propose that simultaneous expression of multiple Py235 ligands enables invasion of a wide range of host erythrocytes even in the presence of antibodies to one or more of the proteins and that this functional redundancy at the protein level gives the parasite phenotypic plasticity in the absence of differences in gene expression.

Show MeSH
Related in: MedlinePlus