Successful modification | The parasite was generated by the genetic modification |
The mutant contains the following genetic modification(s) |
Gene disruption,
Introduction of a transgene,
Introduction of a transgene
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Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 26417110 |
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 820cl1m1cl1 (RMgm-164)
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Other information parent line | P. berghei ANKA 820cl1m1cl1 (RMgm-164) is a reference ANKA mutant line which expresses GFP under control of a male and RFP under control of a female gametocyte specific promoter. This reference line does not contain a drug-selectable marker (PubMed: PMID: 19438517). |
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The mutant parasite was generated by |
Name PI/Researcher | Yuda M; Kato T |
Name Group/Department | Department of Medical Zoology |
Name Institute | Mie University School of Medicine |
City | Mie |
Country | Japan |
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Name of the mutant parasite |
RMgm number | RMgm-1341 |
Principal name | AP2-G2(−)820 |
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 | No mature male or female gametocytes are formed. No exflagellation. Evidence is presented that sexually committed parasites (trophozoites) are formed within red blood cells but that these parasites abort development before morphological features of sexual differentiation are visible at the light-microscopic level. |
Fertilization and ookinete | No mature male or female gametocytes are formed. No exflagellation. No oocysts are formed. |
Oocyst | No mature male or female gametocytes are formed. No exflagellation. No oocysts are formed. |
Sporozoite | Not tested |
Liver stage | Not tested |
Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of AP2-G2. In addition, it expresses GFP in male gametocytes and RFP in female gametocytes.
Protein (function)
Apetala 2 (AP2)-family proteins are transcription factors that have DNA-binding domains of 60 amino acids called AP2 domains. Recently, AP2 genes have been found in the genomes of Plasmodium parasites. In P. falciparum 27 AP2-family genes have been identified. Among these genes, 26 are conserved in the other Plasmodium species whose entire genomes have been sequenced. Each member of this family has 1 to 4 AP2 domains, and the amino acid sequences of these domains are highly conserved among Plasmodium orthologs.
Phenotype
No mature male or female gametocytes are formed. No exflagellation. Evidence is presented that sexually committed parasites (trophozoites) are formed within red blood cells but that these parasites abort development before morphological features of sexual differentiation are visible at the light-microscopic level.
Evidence is presented that the lack of AP2-G2 expression did not abrogate sexual commitment or sex determination but did cause marked developmental defects in the gametocytes, together with a marked reduction of sex-specific gene expression.
Evidence is presented that AP2-G2 is a transcriptional repressor in sexually committed trophozoites. Evidence is presented that most of these target genes of AP2-G2 binding are required for asexual proliferation of the parasites in the blood, suggesting that AP2-G2 blocks the program of asexual replication to promote conversion to the sexual stage. These 'asexual' genes were upregulated in the parasites lacking expression of AP2-G2
Additional information
The AP2-G2(−)820 parasites showed the same phenotype observed in the AP2-G2(−) populations prepared from wild-type parasites (RMgm-1340); i.e., they produced no mature gametocytes. Based on flow cytometric analysis, the signal strengths of both fluorescent proteins in AP2-G2(−)820 parasites were markedly lower than in the original parasites. However, the ratio of RFP-positive to GFP-positive cells was similar between AP2-G2(−) parasites and the original parasites (0.95 and 1.16, respectively), and the two populations presented no overlap with each other, indicating that AP2-G2(–)820 parasites commit to one sex at a sex ratio similar to that in the original 820cl1m1cl1 parasites.
In analyses using mutant P. berghei parasites expressing GFP-tagged AP2-G2 (AP2-G2::GFP parasites; RMgm-1342), it was found that AP2-G2 was specifically expressed in female and male gametocytes. The GFP signal was solely observed in the nucleus, suggesting that AP2-G2 acts as a transcription factor in gametocytes. In a temporal profiling analysis of AP2-G2 expression using synchronized blood cultures, expression was first observed from 16 h after erythrocyte invasion (hpi) until development into mature male or female gametocytes. The timing of expression correlated well with the onset of morphological divergence from the asexual stage (16–18 hpi), strongly suggesting that this transcription factor is involved in gametocyte-specific gene expression.
Other mutants
See link for other AP2-G2 mutants |