| Successful modification | The parasite was generated by the genetic modification |
| The mutant contains the following genetic modification(s) |
Gene disruption,
Introduction of a transgene
|
| Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 21098480
|
| MR4 number |
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| Parent parasite used to introduce the genetic modification |
| Rodent Malaria Parasite | P. berghei |
| Parent strain/line | P. berghei ANKA |
| Name parent line/clone |
P. berghei ANKA 2.34
|
| Other information parent line | P. berghei ANKA 2.34 is a cloned, gametocyte producer line of the ANKA strain (PubMed: PMID: 15137943). |
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| The mutant parasite was generated by |
| Name PI/Researcher | A.Z. Tremp; J.T. Dessens |
| Name Group/Department | Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases |
| Name Institute | London School of Hygiene & Tropical Medicine |
| City | London |
| Country | UK |
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| Name of the mutant parasite |
| RMgm number | RMgm-601 |
| Principal name | IMC1h-KO |
| Alternative name | |
| Standardized name | |
| Is the mutant parasite cloned after genetic modification | Yes |
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| Phenotype |
| Asexual blood stage | Not different from wild type |
| Gametocyte/Gamete | Not different from wild type |
| Fertilization and ookinete | Normal numbers of ookinetes are produced. Mature ookinetes showed abnormal morphology. Ookinetes were wider, shorter and possessed a bulging area typically in the central part of the cell. Infectivity of ookinetes was reduced (ookinetes produced ~30-fold less oocysts in A. stephensi). |
| Oocyst | Infectivity of ookinetes was reduced (ookinetes produced ~30-fold less oocysts in A. stephensi). Oocysts appeared to develop normally, forming large numbers of sporozoites. However, all sporozoites were of abnormal shape, typically possessing a bulging area near the middle of the sporozoite. No sporozoites were detected in salivary glands. |
| Sporozoite | Oocysts appeared to develop normally, forming large numbers of sporozoites. However, all sporozoites were of abnormal shape, typically possessing a bulging area near the middle of the sporozoite. No sporozoites were detected in salivary glands. |
| Liver stage | Not tested |
| Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of Inner membrane complex protein 1h (IMC1h)
Protein (function)
The imcb1h gene belongs to small 'family' of conserved genes that express putative membrane skeleton proteins which contain domains that share sequence homology to domains of articulins, proteins of membrane skeleton of free-living protists and show homology to the inner membrane complex protein 1 (TgIMC1) of the subpellicular network of Toxoplasma gondii tachyzoites (Khater, E.I., et al. 2004, J. Cell. Biol. 167, 425-32) . In Plasmodium eight conserved IMC1 protein family members have been identified, named IMC1a-IMC1h. Two of these, IMC1a and IMC1b, were shown to be differentially expressed in sporozoites and ookinetes, respectively, and to form part of their pellicle structures in P. berghei. IMC1a and IMC1b are structurally and functionally homologous and involved in parasite morphology, mechanical strength, gliding motility and infectivity, in accordance with their roles as membrane skeleton proteins (see also mutanst RMgm-147 and RMgm-148 lacking expression of IMC1b and IMC1a). IMC1h, is found in the pellicle of both ookinetes and sporozoites (see mutant RMgm-600) and acts in a very similar way to IMC1b and IMC1a (see below)
Phenotype
Phenotype analyses of a mutant expressing GFP-tagged IMC1h (RMgm-600) shows expression of the protein in ookinetes, sporulating oocysts and sporozoites with evidence for a pellicaular location.
Phenotype analyses of the mutant lacking IMC1h indicates a role of this protein in morphology/shape of ookinetes and sporozoites and in motility of both stages.
Mature ookinetes showed abnormal morphology. Ookinetes were wider, shorter and possessed a bulging area typically in the central part of the cell. This phenotype is the same as that observed in ookinetes lacking expression of IMC1b (RMgm-147) and is consistent with a role of IMC1h as a membrane skeleton protein.
Infectivity of ookinetes was reduced (they produced ~30-fold less oocysts. Oocysts appeared to develop normally, forming large numbers of sporozoites. However, all sporozoites were of abnormal shape, typically possessing a bulging area near the middle of the sporozoite reminiscent of sporozoites lacking expression of IMC1a (RMgm-148). No sporozoites were detected in salivary glands.
Analysis of a mutant lacking expression of both IMC1h and IMC1b (RMgm-602) provides evidence that for a direct involvement of IMC1 proteins in gliding motility uncoupled from cell shape.
Additional information
An orthologue of IMC1h was identified in T. gondii, named TgIMC3 (AAT49041). TgIMC3 is a pellicle-associated protein of tachyzoites. The PIMC1h and TgIMC3 proteins share two conserved domains: a central articulin-like domain related to the IMCp domain superfamily (Pfam12314) that defines the alveolins, and a carboxy-terminal domain that is unique to PIMC1h and TgIMC3. None of the Plasmodium MC1h proteins identified possess cysteine motifs at amino- and carboxy-termini described in TgIMC1 and PbIMC1a.
Other mutants
RMgm-147: A mutant lacking expression of IMC1b
RMgm-148: A mutant lacking expression of IMC1a
RMgm-163: A mutant expressing a GFP-tagged form of IMC1b
RMgm-600: A mutant expressing a GFP-tagged form of IMC1h
RMgm-602: A mutant lacking expression of both IMC1h and IMC1b |
*RMgm-601
