| Successful modification | The parasite was generated by the genetic modification |
| The mutant contains the following genetic modification(s) |
Gene mutation
|
| Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 18452513
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| 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
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| 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 | V. Carter; J.T. Dessens |
| Name Group/Department | Department of Infectious and Tropical Diseases |
| Name Institute | London School of Hygiene and Tropical Medicine |
| City | London |
| Country | United Kingdom |
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| Name of the mutant parasite |
| RMgm number | RMgm-115 |
| Principal name | ∆SRCR/EGFP |
| 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 | Not different from wild type |
| Oocyst | Normal numbers of oocysts are formed. Highly reduced formation of sporozoites within the oocysts. Only a few oocysts were observed that contained sporozoites. |
| Sporozoite | Highly reduced formation of sporozoites within the oocysts. In samples of pooled oocyst-infected guts, gently homogenized to release sporozoites, no sporozoites were detected (compared with >10 000 sporozoites per gut in wild type with comparable oocyst numbers), although occasionally a sporulating oocyst was observed by light microscopy. These appeared normal and released sporozoites when subjected to gentle pressure. Moreover, these sporozoites displayed normal CS expression on their surface, and left CS reactive trails, indicating they possessed gliding motility. No sporozoites were detected in salivary glands. No transmission of parasites to naïve mice by infected mosquito bites. |
| Liver stage | Not different from wild type |
| Additional remarks phenotype | Mutant/mutation
The mutant expresses a mutated form of PbSR (P. berghei Scavenger Receptor-like protein; PSLAP; LAP1; LCCL domain containing protein CCp3). The mutated protein lacks the two central SRCR domains (see below) from the PbSR protein which is (c-terminal) tagged with EGFP.
Protein (function)
The pbsr gene is a member of a small conserved gene family, encoding proteins with multiple adhesive domains, for example a Lgl1 (LCCL)-lectin adhesive domain. In P. falciparum the LCCL domain-containing proteins are termed PfCCp's. PbSR contains four LCCL domains; a LH2 (lipoxygenase homology 2) domain; two SR (scavenger receptor cysteine-rich) domains and a PTX/LamG (pentraxin/laminin-G) domain related to concanavalin A-like module.
Phenotype
Phenotype analyses of mutants lacking the complete PbSR protein (RMgm-113, RMgm-114) indicate a role of PbSR in the formation of sporozoites in the oocyst (see also Additional information). The phenotype analyses of the mutant that expresses the mutated form of PbSR indicate that the SRCR domains are essential for sporozoite formation.
Additional information
The protein is expressed in female gametocytes and in ookinetes. In the ookinetes PbSR is associated with crystalloids, transient organelles that form in developing ookinetes and disappear after ookinete-to-oocyst transition (Carter, V. et al., 2008, Mol. Microbiol. 68, 1560-1569; RMgm-116).
A P. falciparum mutant has been generated that lacks expression of CCp3 (PbSR). This mutant showed 'normal' sporozoite formation (sporulation) within oocysts in Anopheles freeborni. Howver, no hemocoel or salivary gland sporozoites were detected (Pradel G. et al., 2004, J. Exp. Med 199, 1533-1544).
Other mutants
RMgm-113: A mutant lacking PbSR
RMgm-114: A mutant lacking PbSR
RMgm-116: A mutant expressing a GFP- and mCherry-tagged version of PbSR
RMgm-117: A mutant expressing a GFP- tagged version of PbSR |
*RMgm-115
