Successful modification | The parasite was generated by the genetic modification |
The mutant contains the following genetic modification(s) |
Gene disruption
|
Reference (PubMed-PMID number) |
Reference 1 (PMID number) : 19068099 |
MR4 number |
|
top of page |
Parent parasite used to introduce the genetic modification |
Rodent Malaria Parasite | P. yoelii |
Parent strain/line | P. y. yoelii 17XNL |
Name parent line/clone |
Not applicable
|
Other information parent line | 17XNL is a non-lethal strain of P. yoelii |
top of page |
The mutant parasite was generated by |
Name PI/Researcher | A.M. Vaughan; S.H.I. Kappe |
Name Group/Department | Not applicable |
Name Institute | Seattle Biomedical Research Institute |
City | Seattle |
Country | USA |
top of page |
Name of the mutant parasite |
RMgm number | RMgm-183 |
Principal name | fabb/f- |
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 different from wild type |
Sporozoite | Normal numbers of salivary gland sporozoites are produced. Sporozoites are not infectious to mice as shown by the absence of blood infections after inoculation of 50.000 sporozoites. |
Liver stage | Normal numbers of salivary gland sporozoites are produced. Sporozoites are not infectious to mice as shown by the absence of blood infections after inoculation of 50.000 sporozoites. At 12 and 24 h after injection of sporozoites liver stages showed normal development that was indistinguishable from wild type, i.e. they invaded hepatocytes, formed a parasitophorous vacuole (PV), transformed into trophozoites and initiated schizogony. However, by 44 h the size of the liver stages was significantly less than that of wild type. In addition, abnormal progression of nuclear division became apparent. No expression of MSP1 was detected. No mature merozoites are formed and released, resulting in the absence of blood infection. |
Additional remarks phenotype | Mutant/mutation
The mutant lacks expression of FABB/F.
Protein (function)
FABB/F is an enzyme of the bacterial like type II fatty acid biosynthesis (FAS-II) pathway. In Plasmodium FAS-II enzymes have been localized to the apicoplast, a nonphotosynthetic plastid organelle of cyanobacterial origin.
FAS-II requires acetyl-Coenzyme A (CoA), which can be converted from pyruvate by the pyruvate dehydrogenase complex. Acetyl-CoA carboxylase converts acetyl-CoA to malonyl-CoA, which is tethered to an acyl carrier protein (ACP) by malonyl-CoA:ACP transacylase (FabD). This produces malonyl-ACP, which, in conjunction with acetyl-CoA, is acted upon by β-ketoacyl-ACP synthase III (Fab H) to form β-ketoacyl-ACP. This precursor enters the FAS-II elongation cycle, mediated by FabB/F (β-ketoacyl-acyl-carrier-protein (ACP) synthase), FabG (β-ketoacyl-ACP reductase), FabZ/A (β-hydroxyacyl-ACP dehydratase), and FabI (trans-2-enoyl-ACP reductase). These four FAS-II enzymes iteratively catalyze the addition of two carbon chains to a growing fatty acyl carbon chain via condensation, reduction, dehydration, and reduction steps, respectively.
Phenotype
The phenotype analyses show that FABB/F is not essential for blood stage development, mosquito stage development and initial infection of the liver. The results indicate an essential role in the formation of infective liver stage merozoites demonstrating the importance of FASII pathway for synthesis of fatty acids during late liver stage development.
Additional information
Other mutants
RMgm-180: A mutant expressing myc tagged FABI
RMgm-181: A mutant expressing myc tagged FABZ
RMgm-182: A mutant expressing myc tagged FABG
RMgm-184: A mutant lacking expression of FABz
RMgm-197: A mutant lacking expression of FABI
|