Figure 3.

Nuclear envelope visualized using BODIPY TRc and U-ExM during mitosis of P. falciparum blood-stage. (a) MCMBP^HADD parasites were cultured in the presence of Shld1. Parasites were then prepared for U-ExM, stained with a nuclear stain (SYTOX, in cyan), anti-tubulin (in magenta), a membrane stain (BODIPY Texas Red ceramide (TRc), in white), and a protein stain (NHS Ester, in grayscale), and visualized using Airyscan microscopy. Hemispindle arrow indicates microtubule not associated with chromatin. Interpolar spindle arrow indicates chromatin-free bridge region. Images containing BODIPY TRc are average intensity projections, while those with NHS ester are maximum intensity projections. Slice-by-slice videos of images in 3a found in Videos S9–S11. Scale bars as labelled in each image, solid bars = XY scale, dashed bar = combined depth of slices used for Z-projection. (b) Model for the progression between observed microtubule structures as inferred from [16]. Hemispindles are first observed, but retract before formation of the mitotic spindle once DNA replication has occurred. After the formation of the mitotic spindle, two masses of DNA separate from each other but remain in a shared nuclear envelope with their MTOCs connected by the interpolar spindle. The nucleus then undergoes nuclear fission, separating the two separated DNA masses into daughter nuclei. Following nuclear fission, the hemispindle reforms and further rounds of mitosis occur.