Episomal expression of GFP-tagged Pfnek-4 protein multinucleated-schizont stage from transgenic 3D7 parasites expressing GFP-tagged Pfnek-4 controlled by cognate (Pfnek-4) promoter. Overlay between the green and blue channels, and corresponding DIC images are shown as well. Scale bars, 2.0 μm. While the bulk of examined schizonts did not show any detectable signal, as expected for a protein thought to be gametocyte-specific, fluorescence microscopy of asexual stage cultures consistently identified a small subpopulation of schizonts with dots (single or doublets) of concentrated Pfnek-4-GFP protein associated with nuclei. Fluorescence was never detected in ring and trophozoite stages. Noteworthy, all nuclei within a single schizont appeared to be associated with punctuate Pfnek-4-GFP fluorescence from early developing schizont to multinucleated schizonts (right). Reininger L, Garcia M, Tomlins A, Müller S, Doerig C. The Plasmodium falciparum, Nima-related kinase Pfnek-4: a marker for asexual parasites committed to sexual differentiation. Malar J. 2012 Jul 31;11(1):250.

Transgenic expression of GFP-tagged Pfnek-4 and Pfnek-2 proteins in P. falciparum parasites. Live images of Hoechst-stained P. falciparum 3D7 transfectants episomally expressing Pfnek-2-GFP (A) or Pfnek-4-GFP (B) proteins under cognate Pfnek-2 and Pfnek-4 promoters, respectively. A. The Pfnek-2-GFP fluorescence (green) is not observed in stage II gametocytes (G-II), but appears to be associated to microtubule structures in more mature stage IV gametocytes (G-IV). B. The Pfnek-4-GFP fluorescence (green) appears as single dots associated with Hoechst-stained nuclear bodies (blue) in a subset of schizonts (S) and stage II gametocytes (G-II). DIC images are shown as well.Doerig C, Reininger L. Nima- and Aurora-related kinases of malaria parasites. Biochim Biophys Acta. 2013 1834(7):1336-45