Fig. 1.

Giardia microtubule cytoskeleton emphasizing interphase basal body positions and migration during mitosis. A schematic representation of the characteristic teardrop shape of Giardia and the cytoskeletal features of the cell is shown in panel (a), including: the basal bodies (bb), four pairs of flagella (afl = anterior, cfl = caudal, pfl = posteriolateral, vfl = ventral), median body (mb), and ventral disc (vd). Anti-tubulin immunostaining reveals the cytoplasmic lengths of all eight flagella, which begin at the basal bodies located between the two nuclei labeled with DAPI (b). Panel c shows a schematic of the basal body tetrads arrangements and their association with specific flagellar axonemes (A/A’ = anterior, C/C’ = caudal, P/P’ = posteriolateral, V/V’ = ventral, N = nuclei). A transmission electron micrograph (TEM) of the anterior region of the cell in panel d shows the organization the basal bodies and their associated flagellar axonemes (Abb/A’bb = anterior basal body, Cbb/C’bb = caudal basal body, Pbb = posteriolateral basal body, and AAX = anterior axonemes). The ventral disc is also nucleated from the caudal basal bodies. A TEM cross section of a mitotic cell in panel e shows the migration of basal bodies from their interphase position between the two nuclei (panel c) to the spindle poles, where they are associated with the spindle microtubules and flagellar axonemes (i.e., one anterior axoneme (AAX) is visible)