Mutant/mutation
The mutant expresses a C-terminal 3xHA-tegged version of TCTP.
CRISPR/Cas9 was used to tag the tctp gene with 3xHA at the 5′ end of the gene and at the same time generated parasites with ((RMgm-5572) or without the 5′UTR intron (RMgm-5571).

Protein (function)
Histamine releasing factor (HRF), originally classified as a tumor protein (translationally controlled tumor protein, TCTP) in mouse erythroleukemia, is found in a wide range of eukaryotes including yeast, plants and animals. The name TCTP was coined as a consequence of cDNA cloning from a human mammary carcinoma and based on the fact that TCTP is regulated at the translational level. HRF plays many different functions and is involved in many physiological processes such as cell proliferation, stress and heat shock responses, and cell death. As an intracellular product, HRF/TCTP has a calcium and tubulin binding properties and has been shown to transiently associate with microtubules during cell cycle. As a calcium-binding protein HRF/TCTP was found to be up-regulated in response to a loss of calcium homeostasis which could be part of a role of HRF in general stress response. As a secreted product, HRF/TCTP has immuno-modulatory roles. In humans, HRF/TCTP induces the release of histamine and modulates cytokine secretion from basophils, eosinophils, and T cells. HRF/TCTP was found to have an inflammatory role in mouse models of asthma and allergy.
HRF is also expressed by a number of eukaryotic parasites, including Plasmodium. Plasmodium HRF/TCTP, which has a high homology to human HRF/TCTP (their amino acid sequences are 33% identical and 54% similar) has been proposed to play an important role during the erythrocytic phase of malarial infection (MacDonald et al., 2001).

Phenotype
Reduced parasite growth/multiplication of blood stages (and increased survival of infected mice).
The gametocyte rates of the parasite clones with the 3xHA-tag (pytctp(+IN+HA); RMgm-5572), pytctp−IN+HA and pytctp+IN+HAc) were significantly lower than WT 17XL or the untagged clones without the intron (pytctp(−IN)), indicating that the introduction of 3xHA-tag in pytctp influenced the gametocyte production. No oocyst/sporozoites the parasites bearing 3xHA-tag in pytctp.

See also mutant RMgm-5570 for a P. yoelii mutant paraste lacking expression of TCTP
Reduced growth/multiplication of asexual blood stage parasites. (Severely) reduced gametocyte production. No oocyst/sporozoite production.

See RMgm-1135, RMgm-1507 and RMgm-2979 for P. berghei mutants lacking expression of TCTP with (slightly) different phenotypes (specifically with regard to sexual/mosquito developement).

Additional information
Evidence is shown for the following:
The pytctp(−IN+HA) parasites without the 5’UTR intron had lower mRNA levels than those of WT 17XL, while the transcript levels of pytctp+IN+HA parasite (RMgm-5572) carrying HA-tagged gene with 5′UTR intron (pytctp+IN+HA) were comparable to those of the WT parasites.
The PyTCTP protein was expressed at higher levels in the parasites with 5’UTR intron than in those without 5’UTR intron in ring, trophozoite and schizont stages with HA-tag at either the N- or C-terminal

From the Abstract:
' We showed that promoters with 5′UTR introns had higher activities in driving gene expression than those without 5′UTR introns. The results were confirmed in recombinant parasites expressing an HA‑tagged gene (pytctp) driven by promoter with or without 5′UTR intron'. ....'Finally, the 5′UTR introns were alternatively spliced in different parasite development stages, suggesting an active mechanism employed by the parasites to regulate gene expression in various developmental stages'.

Other mutants