Localization of 6.1 products using confocal microscopy. A. Segmenters labelled with mouse anti-161 serum (left, superimposition; middle, FITC; right, propidium iodide). B. Segmenters labelled with mouse anti-261 serum. C. Ring stages labelled with mouse anti-161 serum D. Ring labelled with mouse anti-261 serum. The images obtained on segmenters (Fig. A and B for the anti-161 and anti-261 antisera respectively) indicated that 6.1 was a nuclear protein. Serial confocal images showed staining all over the nuclear mass, colocalized with the DNA. All schizonts stained with propidium iodide were labelled with the anti-161 and anti-261 sera, indicating expression of the 6.1 gene by all parasites. Both antisera also reacted with the nucleus of ring stages (Fig. C and D).Bischoff E, Guillotte M, Mercereau-Puijalon O, Bonnefoy S. A member of the Plasmodium falciparum Pf60 multigene family codes for a nuclear protein expressed by readthrough of an internal stop codon. Mol Microbiol. 2000 35:1005-16.