Mutant/mutation
The mutant expresses a c-terminal GFP-tagged DOZI (protein development of zygote inhibited; ATP-dependent RNA helicase, putative).

Protein (function)
DOZI is an RNA helicase that is highly up-regulated in female gametocytes and shows high sequence homology to the DDX6 family of RNA helicases.  It contains domains involved in RNA-binding and RNA-unwinding activity.  In other eukaryotes the DDX6 family of DEAD-box RNA helicases is tightly linked both to storage of mRNAs encoding proteins associated with progression through meiosis into translationally silent mRNPs and with the transport of mRNA to degradation centers in the cell (P-bodies). These helicases are found in organisms as diverse as yeast (e.g., Dhh1p) and humans (e.g., RCK/p54). The phenotype analysis of a mutant lacking expression of DOZI (RMgm-100)  indicate that DOZI has a central role in the silencing and maintenance of steady-state levels of a population of gametocyte-specific transcripts. The loss of DOZI severely affected the capacity of the parasite to store and stabilize a discrete subset of mRNAs in the female gametocyte, resulting in a failure to synthesize specific proteins and to complete normal zygote development.  Translational repression of transcripts encoding these proteins in Plasmodium may function to specifically regulate gene expression during meiosis in the zygote.

Phenotype
The phenotype analyses demonstrate normal fertilisation and zygote/ookinete development indicating that the function of DOZI is not affected by the GFP-tag (see RMgm-100 for the phenotype of a mutant lacking expression of DOZI).
A punctate GFP-fluorescence pattern that appeared to be restricted to the cytoplasm of female gametocytes was observed. Fluorescence in situ hybridization (FISH) analysis of the localization of translationally repressed transcripts of genes encoding ookinete surface proteins P25 and P28, showed also a punctate localization pattern comparable to that of DOZI-GFP, indicating that the repressed transcripts and DOZI are distributed similarly in the cytoplasm.
Immunoprecipitations of the DOZI::GFP fusion protein from gametocyte lysates have been made with monoclonal anti-GFP antibodies. The eluates have been analyzed for DOZI protein and transcript content, showing the presence of (known) translational repressed transcripts.

Additional information:
This mutant has also been used for analysis of the protein content by LC-MS/MS mass-spectrometry of imuunoprecipitations of the DOZI::GFP fusion protein from gametocyte lysates (see PubMed, PMID number 20169188). This analysis identified a number of proteins that show homology to proteins found in metazoan mRNP granules involved in translational repression of mRNAs indication the presence of messenger ribonucleoprotein (mRNP) bodies in gametocytes with homology to metazoan mRNP granules/P-bodies (see also mutant RMgm-358 for characterization of another protein, CITH; CAR-I/Trailer Hitch Homolog,  that is present in the mRNPs of gametocytes).

Other mutants
RMgm-100: A mutant lacking expression of DOZI.
RMgm-361: A mutant which lacks expression of DOZI  and expresses GFP under control of a male and RFP under control of a female gametocyte specific promoter.