| Successful modification | The parasite was generated by the genetic modification |
| The mutant contains the following genetic modification(s) |
Gene tagging
|
| Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 19181869
|
| MR4 number |
|
| top of page |
| 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 507cl1 (RMgm-7)
|
| Other information parent line | P.berghei ANKA 507cl1 (RMgm-7) is a reference ANKA mutant line which expresses GFP under control of a constitutive promoter (PubMed: PMID: 16242190). |
| top of page |
| The mutant parasite was generated by |
| Name PI/Researcher | S. Engelmann; K. Matuschewski |
| Name Group/Department | Department of Parasitology |
| Name Institute | Heidelberg University School of Medicine |
| City | Heidelberg |
| Country | Germany |
| top of page |
| Name of the mutant parasite |
| RMgm number | RMgm-232 |
| Principal name | siap-1/mcherry |
| Alternative name | |
| Standardized name | |
| Is the mutant parasite cloned after genetic modification | Yes |
| top of page |
| Phenotype |
| Asexual blood stage | Not different from wild type |
| Gametocyte/Gamete | Not different from wild type |
| Fertilization and ookinete | Not different from wild type |
| Oocyst | SIAP-1/mCherry oocysts produced normal numbers of sporozoites, which invaded mosquito salivary glands. |
| Sporozoite | SIAP-1/mCherry oocysts produced normal numbers of sporozoites, which invaded mosquito salivary glands. Normal numbers of salivary gland sporozoites were formed that were infective C57/BL6 mice.
The fusion protein SIAP-1/mCherry was abundantly expressed in oocyst-derived and salivary gland sporozoites. In both immature and mature sporozoites, the protein showed a polarized distribution predominant at the apical tip of the parasites. In addition to this apical concentration, SIAP-1/mCherry was also detected as distinct patches distributed along the parasite. |
| Liver stage | Normal numbers of salivary gland sporozoites were formed that were infective C57/BL6 mice.
In transforming sporozoites 4h post-infection of HepG2 cells in vitro, SIAP-1/mCherry was detected in distinct patches, without clear apical polarization. These dotted structures were still detected 24h post-infection, although at a lower intensity, but had completely disappeared in mature liver stages 72h post-infection |
| Additional remarks phenotype | Mutant/mutation
The mutant expresses a (C-terminal) mCherry-tagged form of SIAP-1 (Sporozoite Invasion-Associated Protein-1).
Protein (function)
SIAP-1 orthologs have been found exclusively in apicomplexan hemoprotozoa, parasites that are transmitted by arthropod vectors, e.g., Plasmodium, Babesia, and Theileria species (and is absent in, for example, Toxoplasma and Cryptosporidium). SIAP1 was first discovered in a systematic screen for P. falciparum sporozoite antigens recognized by sera from individuals that were immunized with irradiated sporozoites and termed antigen 17 (ag17). Subsequently, the P. yoelii ortholog was isolated in a suppression subtractive hybridization screen for genes that are specifically upregulated in sporozoites (S5) compared to blood stages. Mutant parasites lacking expression of SIAP-1 showed defects in egress of sporozoites from the oocysts and invasion of the salivary gland by the sporozoites (see RMgm-109, RMgm-233, RMgm-234).
Phenotype
The phenotype analyses indicate that the C-terminal tagging of SIAP-1 had no detrimental effect on P. berghei infectivity. The phenotype analyses indicate specific expression of SIAP-1 in sporozoites and liver stages. In both immature and mature sporozoites, the SIAP-1/mCherry protein showed a polarized distribution predominant at the apical tip of the parasites. In addition to this apical concentration, SIAP-1/mCherry was also detected as distinct patches distributed along the parasite. These patches were sometimes clearly distributed at the periphery of the parasite, suggesting a possible association of SIAP-1 with the sporozoite pellicle.
Additional information
No change in the distribution of SIAP-1/mCherry was observed during the gliding of motile sporozoites.
Other mutants
RMgm-109: A mutant lacking expression of SIAP-1
RMgm-233: A mutant lacking expression of SIAP-1
RMgm-234: A mutant lacking expression SIAP that expresses GFP under control of the sporozoite specific csp promoter. |
*RMgm-232
