Redistribution of Golgi Stacks and Other Organelles during Mitosis and Cytokinesis in Plant Cells,

Abstract

We have followed the redistribution of Golgi stacks during mitosis and cytokinesis in living tobacco BY-2 suspension culture cells by means of a green fluorescent protein-tagged soybean ␣-1,2 mannosidase, and correlated the findings to cytoskeletal rearrangements and to the redistribution of endoplasmic reticulum, mitochondria, and plastids. In preparation for cell division, when the general streaming of Golgi stacks stops, about one-third of the peripheral Golgi stacks redistributes to the perinuclear cytoplasm, the phragmosome, thereby reversing the ratio of interior to cortical Golgi from 2:3 to 3:2. During metaphase, approximately 20% of all Golgi stacks aggregate in the immediate vicinity of the mitotic spindle and a similar number becomes concentrated in an equatorial region under the plasma membrane. This latter localization, the "Golgi belt," accurately predicts the future site of cell division, and thus forms a novel marker for this region after the disassembly of the preprophase band. During telophase and cytokinesis, many Golgi stacks redistribute around the phragmoplast where the cell plate is formed. At the end of cytokinesis, the daughter cells have very similar Golgi stack densities. The sites of preferential Golgi stack localization are specific for this organelle and largely exclude mitochondria and plastids, although some mitochondria can approach the phragmoplast. This segregation of organelles is first observed in metaphase and persists until completion of cytokinesis. Maintenance of the distinct localizations does not depend on intact actin filaments or microtubules, although the mitotic spindle appears to play a major role in organizing the organelle distribution patterns. The redistribution of Golgi stacks during mitosis and cytokinesis is consistent with the hypothesis that Golgi stacks are repositioned to ensure equal partitioning between daughter cells as well as rapid cell plate assembly.

Characterization of AtCDC48. Evidence for Multiple Membrane Fusion Mechanisms at the Plane of Cell Division in Plants

“…6, A [top cell], and B, see black arrow). In contrast, ␣-mannosidase was not observed within the division plane (data not shown) as previously demonstrated (Nebenfü hr et al, 2000). Double immunolabeling with anti-SYP31 and anti-␣-mannosidase was not performed because both primary antibodies are of rabbit origin.…”

Vesicle Dynamics during Plant Cell Cytokinesis Reveals Distinct Developmental Phases

“…This means that, during IPA, the components forming the cell plate will have a mosaic origin and can derive from both the ER and the Golgi that localize in the vicinity of the future cell plate (Nebenführ et al, 2000;Rybak et al, 2014) as well as from the outer envelope of the cell (plasma membrane and parental cell wall), although the respective contribution of one source may dwarf the other.…”

“…They are proposed to restrain the accumulation and fusion of vesicles to the midzone or initiation site Higaki et al, 2008) and to guide the phragmoplast microtubule-binding myosin VIII, thus guiding the margin of the expanding cell plate toward the cortical division site Molchan et al, 2002;Van Damme et al, 2004;Panteris, 2008;Wu and Bezanilla, 2014). The precise role of actin in cytokinesis is poorly understood and controversial, since latrunculin B (LatB), an inhibitor of actin polymerization, was observed to inhibit cell plate expansion or impede its straightening by some (Nebenführ et al, 2000;Higaki et al, 2008;Zhang et al, 2009;Wu and Bezanilla, 2014) but not by others (Van Damme et al, 2011). Additional evidence for the role of actin stems from the administration of the myosin ATPase inhibitor 2,3-butanedion monoxime (BDM; Nebenführ et al, 2000;Higaki et al, 2008;Zhang et al, 2009), which inhibits cell plate expansion, suggesting an important role for an actomyosin-based mechanism in the centrifugal expansion and the alignment of the cell plate.…”

“…The precise role of actin in cytokinesis is poorly understood and controversial, since latrunculin B (LatB), an inhibitor of actin polymerization, was observed to inhibit cell plate expansion or impede its straightening by some (Nebenführ et al, 2000;Higaki et al, 2008;Zhang et al, 2009;Wu and Bezanilla, 2014) but not by others (Van Damme et al, 2011). Additional evidence for the role of actin stems from the administration of the myosin ATPase inhibitor 2,3-butanedion monoxime (BDM; Nebenführ et al, 2000;Higaki et al, 2008;Zhang et al, 2009), which inhibits cell plate expansion, suggesting an important role for an actomyosin-based mechanism in the centrifugal expansion and the alignment of the cell plate.…”

The Mitochondrial Cycle of Arabidopsis Shoot Apical Meristem and Leaf Primordium Meristematic Cells Is Defined by a Perinuclear Tentaculate/Cage-Like Mitochondrion

“…Only in certain types of differentiated mammalian cells have reticulate mitochondria been observed (Bakeeva et al, 1978;Bawa and Werner, 1988;BereiterHahn, 1990;Smirnova et al, 1998;Yaffe, 1999b). Similarly, higher plant mitochondria have been typically portrayed as round to sausage-like organelles (Olyslaegers and Verbelen, 1998;Logan and Leaver, 2000;Nebenfü hr et al, 2000;Arimura and Tsutsumi, 2002;Van Gestel and Verbelen, 2002;Logan et al, 2003;Arimura et al, 2004;Logan, 2006a). Although some studies report on the presence of reticulate mitochondria in unperturbed eggs (Kuroiwa et al, 1996(Kuroiwa et al, , 2002 and vascular cell types (Gamalei and Pakhomova, 1981), most of the documented examples of reticular or disc-shaped mitochondria come from mitochondrial mutants (Arimura and Tsutsumi, 2002;Logan et al, 2003) or from cells subjected to experimental perturbations such as low oxygen pressure (Bereiter-Hahn, 1990;Van Gestel and Verbelen, 2002;Logan, 2006a), prolonged cell culturing (Rohr, 1978), or protoplasting (Sheahan et al, 2004(Sheahan et al, , 2005.…”