SummaryRMgm-5339
|
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) : 36898988 |
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 2.34 |
Other information parent line | P. berghei ANKA 2.34 is a cloned, gametocyte producer line of the ANKA strain (PubMed: PMID: 15137943). |
top of page | |
The mutant parasite was generated by | |
Name PI/Researcher | Rashpa R, Brochet M |
Name Group/Department | Faculty of Medicine, Department of Microbiology and Molecular Medicine |
Name Institute | University of Geneva |
City | Geneva |
Country | Switzerland |
top of page | |
Name of the mutant parasite | |
RMgm number | RMgm-5339 |
Principal name | Pama1RBX1 |
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 | Not tested |
Sporozoite | Not tested |
Liver stage | Not tested |
Additional remarks phenotype | Mutant/mutation Phenotype To study the function of SCF(FBXO1), we first attempted to knock out skp1, cul1, and rbx1. The two latter genes were previously suggested to be resistant to disruption in a global gene knockout study and we were also unable to obtain KO populations despite four independent attempts (see RMgm-5330, RMgm-5331, RMgm-5332). We then tagged endogenous genes with an auxin-inducible degron (AID) coupled to an HA epitope tag that allows degradation of the fusion protein in the presence of auxin in a strain expressing the Tir1 protein. However, no significant degradation of the targeted proteins nor defects in exflagellation could be observed upon auxin addition in non-clonal populations. This prevented us to further use this system to interrogate the functions of these proteins across multiple stages. To infer potential function in gametocytes, we then opted for stage-specific knockdowns by placing the endogenous cul1 or rbx1 genes under the control of the pbama1 promoter, which is active in schizonts but virtually silent in gametocytes. Clones were readily obtained, but none of them showed quantifiable defects in exflagellation, possibly due to sufficient expression levels. However, the Pama1CUL1 clone mainly formed retort ookinetes, a phenotype that was partially rescued by fertilisation with competent Nek4-KO microgametes, suggestive of a role for cul1 in either sexual lineage. 'These results indicate that gametocytes express a conserved SKP1/RBX1/CUL1 complex with at least two possible adaptor proteins, FBXO1 and FBXL2. The enrichment of CDPK1 in FBXO1-HA and SKP1-HA immuno-precipitates suggests a possible interplay between phosphorylation and ubiquitination to regulate sexual development.' 'The endogenous skp1, cul1 and rbx1 genes were taged with an auxin-inducible degron (AID) coupled to an HA epitope tag that allows degradation of the fusion protein in the presence of auxin in a strain expressing the Tir1 protein (RMgm-1305; Philip and Waters, 2015). However, no significant degradation of the targeted proteins nor defects in exflagellation could be observed upon auxin addition in non-clonal populations This prevented to further use this system to interrogate the functions of these proteins across multiple stages.' 'To infer potential function in gametocytes, we then opted for stage-specific knockdowns by placing the endogenous cul1 or rbx1 genes under the control of the promoter of the blood-stage schizont-specific promoter ama1 (PBANKA_0915000), which is active in schizonts but silent in gametocytes. Cloned parasite lines expressing cul1 (Pama1CUL1; RMgm-5338) and rbx (Pama1RBX; RMgm-5339) under control of the ama-1 promoter were obtained, but none of these showed quantifiable defects in exflagellation (possibly due to sufficient expression levels?). However, the Pama1CUL1 clone mainly formed retort ookinetes, a phenotype that was partially rescued by fertilisation with competent Nek4-KO microgametes, suggestive of a role for cul1 in either sexual lineage.' We then interrogated the requirement for the putative adaptor proteins FBXO1, FBXL2 and the protein of unknown function PBANKA_1358700 that was enriched in SCFFBXO1 immuno-precipitates. We were able to obtain a KO clonal line for PBANKA_1358700 (RMgm-5340), but no defects in asexual blood stages nor in exflagellation were detected. Other mutants |
top of page | |||||||||||||||||||||||||||
Details of the target gene | |||||||||||||||||||||||||||
Gene Model of Rodent Parasite | PBANKA_0806200 | ||||||||||||||||||||||||||
Gene Model P. falciparum ortholog | PF3D7_0319100 | ||||||||||||||||||||||||||
Gene product | E3 ubiquitin-protein ligase RBX1, putative | ||||||||||||||||||||||||||
Gene product: Alternative name | RBX1 | ||||||||||||||||||||||||||
top of page | |||||||||||||||||||||||||||
Details of the genetic modification | |||||||||||||||||||||||||||
Short description of the mutation | 'Promoter swap' mutant: the promoter of rbx1 replaced by the promoter of ama-1 (PBANKA_0915000) | ||||||||||||||||||||||||||
Inducable system used | No | ||||||||||||||||||||||||||
Short description of the conditional mutagenesis | Not available | ||||||||||||||||||||||||||
Additional remarks inducable system | |||||||||||||||||||||||||||
Type of plasmid/construct | (Linear) plasmid double cross-over | ||||||||||||||||||||||||||
PlasmoGEM (Sanger) construct/vector used | No | ||||||||||||||||||||||||||
Modified PlasmoGEM construct/vector used | No | ||||||||||||||||||||||||||
Plasmid/construct map | |||||||||||||||||||||||||||
Plasmid/construct sequence | |||||||||||||||||||||||||||
Restriction sites to linearize plasmid | |||||||||||||||||||||||||||
Selectable marker used to select the mutant parasite | hdhfr | ||||||||||||||||||||||||||
Promoter of the selectable marker | pbdhfr | ||||||||||||||||||||||||||
Selection (positive) procedure | pyrimethamine | ||||||||||||||||||||||||||
Selection (negative) procedure | No | ||||||||||||||||||||||||||
Additional remarks genetic modification | Restriction/ligation cloning for the promoter swaps: To generate the Pama1 lines for genes of interest (goi) cul1 and rbx1, the plasmid pOB116-ama1 was used. The first ~1000 bp of cul1 and rbx1 were amplified from genomic DNA using the primer pairs 'Pama1goi HR1 forward' and 'Pama1goi HR1 reverse'. The PCR products were Gibson assembled into the pOB116-ama1 plasmid digested with XhoI and EcoRV enzymes. The last ~750 bp of the goi 5′ UTR were amplified using primers 'Pama1goi HR2 forward' and 'Pama1goi HR2 reverse' and Gibson assembled into the modified pOB116-ama1 digested with HindIII and PstI enzymes. Plasmids were digested with the enzymes EcoRV and HindIII to be transfected in P. berghei. | ||||||||||||||||||||||||||
Additional remarks selection procedure | |||||||||||||||||||||||||||
| |||||||||||||||||||||||||||
top of page |