Article |
Address correspondence to William Sullivan, Dept. of Molecular, Cellular, and Developmental Biology, 319 Sinsheimer Laboratories, University of California, Santa Cruz, Santa Cruz, CA 95064. Tel.: (831) 459-4295. Fax: (831) 459-3139. email: sullivan{at}biology.ucsc.edu
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Abstract |
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Key Words: recycling endosome; cytokinesis; arfophilins; Dah; Rab effectors
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Introduction |
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Although the mechanism of constriction is contractile, recent reports have begun to define the role of membrane addition in this process (Finger and White, 2002). A cell undergoing cytokinesis requires significant additional membrane to accommodate the increased surface area of producing two daughter cells. Work in Xenopus relying on a variety of surface-marking techniques indicates that the additional membrane has a different composition from the original membrane (Kalt, 1971; Bluemink and de Laat, 1973; Byers and Armstrong, 1986; Bieliavsky et al., 1992). This suggests that the membrane is not derived from the expansion of preexisting surface membrane, but instead forms through insertion of membrane from internal stores. In plant cells, it is well established that the additional membrane necessary for cytokinesis is provided through a Golgi-based delivery system (Bednarek and Falbel, 2002). In Caenorhabditis elegans ovaries, RNA interference inhibition of Rab11, the small GTPase required for vesicle transport through the recycling endosome (RE), causes cytokinesis defects including furrow regression and scission (Skop et al., 2001). Mutation and RNA interference analyses demonstrate that the t-SNARE syntaxin 1 is required for cytokinesis during early embryogenesis (Burgess et al., 1997; Conner and Wessel, 1999; Jantsch-Plunger and Glotzer, 1999). Lamellar bodies, the ER, and internal lipid stores may also prove important in providing membrane for cytokinesis furrows (Fullilove and Jacobson, 1971; Bluemink and de Laat, 1973; Sanders, 1975; Leaf et al., 1990).
The rapid and simultaneous formation of thousands of furrows during early Drosophila embryogenesis makes this system particularly valuable for studying the recruitment of membrane and other furrow components during cytokinesis. Drosophila development begins with 13 synchronous, rapid, syncytial nuclear divisions. After nine divisions in the interior of the embryo, divisions 1013 occur in the actin-rich cortex, just beneath the plasma membrane (Foe and Alberts, 1983). The nuclei and their associated centrosomes induce a dramatic redistribution of the cortical actin. During interphase, actin concentrates into caps centered above each cortical nucleus and its apically positioned centrosomes. As the nuclei progress into prophase, the centrosomes migrate toward opposite poles and the actin caps undergo a dramatic redistribution to form an oblong ring outlining each nucleus and its associated separated centrosome pair (Karr and Alberts, 1986; Kellogg et al., 1988). These rings are equivalent in composition to conventional cytokinesis contractile rings and include actin, myosin II, spectrins, cofilin, ARP, anillin, septins, and formins (Miller and Kiehart, 1995; Stevenson et al., 2002). In addition, these components are closely associated with the plasma membrane and are required for the invagination of these rings around the spindles. These rings are referred to as metaphase or pseudocleavage furrows (Schejter and Wieschaus, 1993; Sullivan and Theurkauf, 1995). At metaphase, the furrows invaginate to a depth of 8 µm to form a half shell that encompasses each spindle. During late anaphase and telophase, the metaphase furrows rapidly regress. Centrosome duplication occurs during late anaphase, and the newly formed centrosome pairs locate apically. The actin caps reform directly above the centrosome pairs in the next interphase. This alternation between interphase actin caps and metaphase furrows occurs until interphase of nuclear cycle 14. At this point, the nuclei remain in interphase and an inverted microtubule basket, which originates from an apically positioned centrosome pair, guides invagination of the cellularization furrows (for review see Schejter and Wieschaus, 1993). At a depth of 35 µm, the furrows pinch off at their base to form individual mononucleate cells.
Genetic and biochemical analyses indicate that vesicle fusion plays an important role in furrow formation in early Drosophila embryogenesis. Mutations in dynamin, a GTPase involved in endocytic vesicle formation, disrupt cellular furrow formation and result in an abnormal accumulation of vesicles in the cytoplasm (Swanson and Poodry, 1981). Unconventional myosin VI has been shown to be involved in the transport of cytoplasmic particles in the Drosophila embryo, and mutations in this gene cause defects in formation of the metaphase furrows (Mermall et al., 1994; Mermall and Miller, 1995). -Adaptin, a coated vesicle component necessary for receptor-mediated endocytosis, is concentrated apically and laterally around the metaphase and cellularization furrows (Dornan et al., 1997). Syntaxin 1, a t-SNARE involved in vesicle targeting, is also required for cellularization in Drosophila (Burgess et al., 1997). Inhibition of Golgi-based vesicle transport inhibits progression of the cellularization furrow front (Sisson et al., 2000). In addition, a major source of this membrane necessary for the cellularization furrows is derived internally rather than from the plasma membrane (Lecuit and Wieschaus, 2000).
Activities associated with the centrosome are also important for vesicle-mediated metaphase and cellular furrow formation. Insights into the centrosome-associated activities directing these rearrangements have come from the analysis of the maternal effect mutation, nuclear fallout (nuf ). Nuf encodes a pericentrosomal protein that is essential for normal metaphase and cellularization furrow formation. Nuf concentrates at the centrosomes during prophase, when metaphase furrows are forming (Rothwell et al., 1998). In the nuf mutation, microtubule dynamics and distribution appear normal, but remodeling and recruitment of actin to the furrows is disrupted and actin remains abnormally concentrated around the centrosomes. Vesicle-based membrane recruitment to the furrows is also disrupted in nuf-derived embryos (Rothwell et al., 1999; Zhang et al., 2000). These phenotypes lead to the intriguing suggestion that a common mechanism mediates actin remodeling and membrane addition during cytokinesis.
Here, we provide additional insight into these two processes by demonstrating that Nuf is a component of the RE and nuf phenotypes are a consequence of Nuf activities at the RE. Nuf exhibits extensive colocalization with Rab11, a member of the Rab family of small GTPases specific to the RE (Mellman, 1996; Ullrich et al., 1996). In addition, Rab11 and Nuf exhibit a mutual dependence for their normal localization to the RE. Rab11-deficient embryos produce metaphase and cellular furrow defects strikingly similar to those observed in nuf-derived embryos. In accord with these results, recent reports demonstrate that Nuf is a homologue of arfophilin-2 (Arfo2), an ADP ribosylation factor (Arf) effector that also binds Rab11 and influences RE organization (Hickson et al., 2003). Together, these reports suggest that actin remodeling during the initial stages of cytokinesis may in part rely on endosomal-mediated membrane delivery to the site of furrow formation.
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Results |
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Rab11 localizes at the centrosome in the early Drosophila embryo
The mammalian homologue of Nuf, Arfo2 physically associates and colocalizes with Rab11, a key component of the RE (Hickson et al., 2003). Rab11 is required for the integrity of the RE, and is believed to mediate transport of vesicles from the RE to the TGN, early endosome, and plasma membrane via a "slow" recycling route (Ullrich et al., 1996; Ren et al., 1998). Dollar et al. (2002) characterized the pattern of Rab11 localization in the developing Drosophila oocyte. They demonstrated that Rab11 localizes at the posterior pole and is necessary for proper microtubule organization and Oskar mRNA localization. Here, we examine the pattern of Rab11 localization during the cortical divisions in the early Drosophila embryo. Shown in Fig. 2 are triple-stained immunofluorescent images of Rab11 (green), the centrosomal protein centrosomin (Cnn; red), and DNA (blue) during nuclear cycle 12. During interphase, Rab11 exhibits a diffuse punctate localization that concentrates around the nuclei. As the embryos progress into prophase, Rab11 maintains its punctate morphology, but exhibits significantly increased concentration at the centrosomes. During metaphase, the centrosomal concentration of Rab11 decreases and there is a concomitant dispersal of Rab11 throughout the cytoplasm encompassing each chromosomespindle complex. This trend continues as the nuclei enter anaphase. Even though the nuclear envelope is substantially broken down during metaphase and anaphase, Rab11 does not enter the interior nuclear space. During telophase, Rab11 puncta concentrate around the newly formed nuclear envelope. There is a slight increase in the concentration of Rab11 puncta at the centrosomes. Cellularization occurs during the prolonged interphase of nuclear cycle 14. At this time, Rab11 is highly concentrated around the pair of apically located sister centrosomes.
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Nuf and Rab11 colocalize at the centrosome
We performed immunofluorescent analyses using anti-Nuf (red) and anti-Rab11 (green) antibodies (Fig. 3 A). During prophase, when both antigens are highly concentrated in the pericentriolar region, areas of maximal Nuf localization correspond to areas of maximal Rab11 localization (yellow spots). Almost without exception, Nuf colocalizes with Rab11 (inset; few if any red puncta). However, the converse is not true, and in regions more distal from the centrosome, Rab11, but not Nuf, is present (inset; numerous green puncta). During cellularization at interphase of nuclear cycle 14, Nuf and Rab11 exhibit high pericentriolar concentrations and extensive colocalization. As observed for prophase of the cortical divisions, Nuf always colocalizes with Rab11, but there are regions of Rab11 localization in which Nuf is not present. Given that Rab11 is an excellent marker of the RE (Ullrich et al., 1996; Ren et al., 1998), these results support the notion that Nuf localizes to the RE during cortical syncytial divisions and during cellularization at interphase of nuclear cycle 14.
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Functional interactions between Nuf and Rab11
To determine if Nuf is required for pericentriolar Rab11 localization, we examined Rab11 localization in nuf-derived embryos (Fig. 4 A). Wild-type and nuf-derived embryos were triple stained for Rab11 (green), Cnn (red), and DNA (blue). Rab11 exhibits a concentrated punctate distribution around the centrosome during prophase (Fig. 4 A, top row). In nuf-derived embryos, both the punctate distribution and concentration of Rab11 around the centrosomes is completely abolished (Fig. 4 A, second row). Although levels of Nuf at the centrosome are greatly reduced during metaphase, Nuf is required for Rab11 centrosome localization at this stage as well (unpublished data). Nuf is also required for Rab11 localization during cellularization. The robust tight localization of Rab11 around the centrosome during cellularization is absent in nuf-derived embryos (Fig. 4 A, bottom row). We believe the mislocalization of Rab11 in nuf is not a result of a general disruption of the intracellular transport pathway, as staining with Golgi marker Lava-lamp (Sisson et al., 2000) revealed normal Golgi distribution throughout the cell cycle in wild-type and nuf-derived embryos (unpublished data). From this analysis, we cannot determine whether levels of Rab11 protein are reduced in nuf-derived embryos.
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Mutations in Rab11 and Nuf exhibit similar defects in metaphase furrow formation
The nuf maternal-effect mutation specifically disrupts syncytial nuclear divisions only after the nuclei migrate to the cortex (Sullivan et al., 1993). These nuclear defects are a consequence of incomplete metaphase furrow formation, which allows inappropriate fusions between nonsister nuclei (Rothwell et al., 1998). Although the interphase actin caps form normally, large gaps are present in the metaphase and cellularization furrows. The gaps are observed in the earliest stages of furrow formation, suggesting that Nuf disrupts recruitment of actin to the furrows rather than in stabilization of actin once at the furrows. To determine if reduced maternal supplies of Rab11 produced cortical phenotypes similar to those observed in nuf mutations, we used the rab11 transheterozygote described above. The nuclear phenotype is equivalent to nuf. In rab11-derived embryos, nuclear distribution and morphology is normal in premigration and early cortical blastoderm embryos (Fig. 5, top row). However, during the late cortical divisions when the nuclei are more densely packed, the nuclear distribution and morphology is disrupted. In premigration and early cortical embryos, 8% (2/23) exhibit disrupted nuclear morphology. During the late cortical divisions, 65% (31/48) exhibit severely disrupted nuclear morphology. This is indicative of defects in the metaphase furrows that serve to separate neighboring nonsister nuclei (Sullivan et al., 1990).
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Discussion |
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Nuf and Arfo2 are functionally as well as structurally related. In HeLa cells, Arfo2 localizes to the perinuclear TGN with staining also observed at the centrosomes and focal adhesions (Hickson et al., 2003). In Drosophila, Nuf has a similar localization at the centrosomes (Rothwell et al., 1998). Overexpression of either Drosophila Nuf or human Arfo2 in mammalian cells results in a collapse of the late RE to a pericentrosomal region (Hickson et al., 2003). These observations suggest that Nuf and Arfo2 are functionally similar and play a role in maintaining the integrity of the RE.
The fact that both Nuf and Arfo2 contain a conserved Rab11-binding domain provides additional support for a common function at the RE. Similar to Arfs, Rabs are members of a large family of small GTPases involved in the regulation of vesicle-trafficking pathways (Segev, 2001). However, unlike Arfs, they are thought to be involved in vesicle targeting rather than vesicle biogenesis. Rab11 is primarily localized at the RE and plays an essential role in receptor-mediated recycling to the plasma membrane (Ullrich et al., 1996; Sheff et al., 2002). In addition, the Rab11 GTPase cycle is essential for normal RE organization and function (Ullrich et al., 1996). Sequence analysis of Arfo2 and Nuf (Fig. 3 B) reveals a common conserved 20-aa Rab11-binding domain originally identified among members of the Rab11-interacting protein family (Hales et al., 2001; Prekeris et al., 2001). In accord with this observation, Arfo2 and Nuf physically interact with Rab11 (Fig. 3 C; Hickson et al., 2003).
Nuf is closely associated with the RE
Our work indicates that Nuf is primarily associated with the RE in the early Drosophila embryo. Nuf shows extensive colocalization with Rab11 (Fig. 3 A). The most significant difference between the distribution of Rab11 and Nuf in the early embryo is that the former maintains a constant level of pericentriolar staining, whereas levels of the latter oscillate with the cell cycle (Fig. 1, A and B; Fig. 2). During the cortical syncytial divisions, pericentriolar Nuf staining is at its highest levels at prophase and negligible during metaphase and anaphase. We do not know whether this is a result of cycling of Nuf levels, subcellular location, or both. At nuclear cycle 14, Nuf levels are highest during interphase as the cellularization furrows are forming. Thus, maximal pericentriolar levels of Nuf are correlated with metaphase and cellular furrow formation and invagination. Nuf is highly phosphorylated (Rothwell et al., 1998), raising the possibility that its localization and/or levels may be regulated by cell cycledependent kinases.
Nuf dynamics are similar to Rab11 dynamics
Further evidence that Nuf is intimately associated with pericentriolar endosomal material comes from live analysis of Nuf dynamics in the early embryo. This analysis reveals a dynamic punctate distribution of Nuf rapidly moving to and from the centrosome. Dual imaging reveals that these puncta are closely associated with astral microtubules, and disruption of the microtubule network severely disrupts GFP-Nuf distribution and movement (unpublished data). This colocalization and dependency of the microtubule network has also been demonstrated for Rab11 and GFP-Arfo2 (Mammoto et al., 1999; Hickson et al., 2003). In comparison with live fluorescent analysis of GFP-Rab11 in mammalian systems (Sonnichsen et al., 2000), GFP-Nuf shows a similar localization, distribution, and movement pattern. This supports the view that Nuf localizes to the RE and that these images reflect RE dynamics in the Drosophila embryo.
Functional interactions between Nuf and Rab11
Our results also demonstrate a mutual dependence of Nuf and Rab11 for their localization to the RE. In nuf-derived embryos, the robust Rab11 pericentriolar distribution is completely disrupted (Fig. 4 A). Whether Nuf is specifically disrupting Rab11 localization to the RE or more globally disrupting RE integrity is not known. However, we believe the effect of Nuf is specific to the RE, as Golgi morphology and distribution is normal in nuf-derived embryos (unpublished data). The effect of nuf mutations on Rab11 localization is consistent with reports demonstrating that overexpression of GFP-Arfo2 alters the organization of Rab11 in mammalian cells (Hickson et al., 2003).
Conversely, Nuf pericentriolar localization fails in embryos with reduced levels of Rab11 (Fig. 4 B). It has been proposed that endosomes are organized into distinct domains defined by combinations of Rab proteins (Zerial and McBride, 2001). These provide a platform for regulatory/effector proteins to create a distinct fusion-competent domain. The proteins are thought to act cooperatively, and loss of one may destabilize the domain. Nuf and Rab11 may be mutually required for the stable formation of such a domain at the RE of the Drosophila embryo.
Nuf and Rab11 are both required for actin and membrane recruitment during metaphase furrow formation
Analysis of nuclear and cortical cytoskeletal defects in nuf- and rab11-derived embryos supports the idea that Nuf and Rab11 are involved in a similar function at the RE. As observed in the nuf mutation, embryos with reduced levels of Rab11 disrupt the syncytial nuclear divisions only after the nuclei reach the cortex. This phenotype indicates that Rab11 is involved in a process specific to the cortical divisions such as cytoskeletal rearrangements or furrow formation. Also like nuf, rab11-derived embryos exhibit fusions between nonsister nuclei, a hallmark of defective furrow formation (Sullivan et al., 1993).
Previous analysis of nuf-derived embryos revealed normal actin organization during interphase, but gaps occur in the actin network early in the process of furrow formation (Rothwell et al., 1998). Our analysis of rab11-derived embryos revealed an equivalent phenotype with respect to actin; the interphase actin caps form normally, but the actin-based metaphase furrows are disrupted (Fig. 6 A). Previous analysis of actin dynamics in the nuf-derived embryos revealed that actin recruitment during the initial stages of furrow formation is compromised (Rothwell et al., 1999). Our fixed analysis of actin defects in rab11-derived embryos reveals actin gaps at the initial stages of furrow formation. Therefore, the rab11 furrow defects are likely the result of defects in the initial recruitment of actin to the furrows.
Although the nuf mutation only partially disrupts actin recruitment to the invaginating furrows, it has a much more severe effect on membrane recruitment. We have used the Drosophila homologue of the dystrobrevins, Dah, as a marker for furrow membrane (Zhang et al., 1996). Biochemical analysis demonstrated that this protein associates tightly with actin and membrane, suggesting it is involved in linking the cortical cytoskeleton and the plasma membrane (Zhang et al., 2000). Immunofluorescent analysis reveals that it localizes to the plasma membrane and invaginating furrows, as well as vesicles that accumulate at furrow formation sites (Rothwell et al., 1999). These vesicles are often associated with actin, suggesting that they incorporate as a unit into the growing furrow. In nuf-derived embryos, there is some localization of Dah at the furrows; however, most remain in vesicles widely dispersed throughout the cortex (Fig. 6 B; Rothwell et al., 1999). The effect of the rab11 mutation on Dah localization is even more severe. There is no Dah localization at the furrows, and few Dah-containing vesicles are seen throughout the cortex.
nuf and rab11 mutations disrupt membrane recruitment and actin remodeling during the early stages of furrow formation, supporting the argument that these proteins function in a common process at the RE. Analysis of Rab11 function in C. elegans revealed that it also is important for normal furrow progression during cytokinesis (Skop et al., 2001). However, this analysis showed varying degrees of defects during furrow invagination, suggesting a role for Rab11 during either the initial stages or latter stages (or both) of cytokinesis. In the Drosophila embryo, Rab11 appears to be involved in the initial stages of furrow formation when actin is being recruited to the invaginating furrow.
A model for Nuf and Rab11 action at the RE
These analyses indicate that activities of Nuf and Rab11 at the RE influence cortical actin dynamics. Specifically, they direct the recruitment of actin to the sites of metaphase furrow formation. One explanation for this linkage between the endosome and cortical actin dynamics is that membrane and actin are recruited as a unit to the metaphase furrows (Rothwell et al., 1999). Immunofluorescent analysis reveals that Dah-containing vesicles are often tightly associated with actin at the leading edge of the invaginating furrows. Therefore, disrupting membrane recruitment would also disrupt actin recruitment (Fig. 7).
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Cortical actin remodeling and localized plasma membrane expansion not only mediates cytokinetic furrow formation, but also is involved in cell motility, lamellipodia formation, and phagocytosis (Bretscher, 1996; Mellman, 2000). Phagocytosis is particularly interesting because recent work has shown that it occurs through targeted delivery of vesicles from the RE. Accumulation of RE-derived VAMP3-containing vesicles occurs at the site of phagosome formation, and disruption of VAMP3 with tetanus toxin prevents phagosome formation (Hackam et al., 1998; Bajno et al., 2000). As we have demonstrated for metaphase and cellular furrow formation, activity at the RE may also mediate cortical actin cytoskeletal remodeling during phagocytosis.
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Materials and methods |
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Drosophila stocks
The initial characterization of the nuf mutation has been described previously (Sullivan et al., 1993; Rothwell et al., 1998). Oregon-R served as the wild-type control stock (Lindsley and Zimm, 1992). All of the experiments described in this manuscript used the null allele of nuf (nuf1; Sullivan et al., 1993; Rothwell et al., 1998). rab11-deficient embryos were obtained from transheterozygous females bearing the J2D1/93Bi alleles of Rab11 (Jankovics et al., 2001). The J2D1/TM3, Sb and 93Bi/TM3, and Sb stocks were obtained from the Bloomington Drosophila Stock Center (Indiana University, Bloomington, IN). Stocks were maintained on standard maize meal/molasses medium.
Fixation and immunofluorescence
Immunofluorescence analysis was performed as described by Rothwell and Sullivan (2000) and Sisson et al. (2000). Propidium iodide was used to view the DNA. Immunofluorescence analyses using rat anti-Rab11 (supplied by Robert Cohen; Dollar et al., 2002), polyclonal rabbit anti-Nuf (Rothwell et al., 1998), polyclonal rabbit anti-Cnn (supplied by Thomas Kaufman; Indiana University, Bloomington, IN; Megraw et al., 1999), and anti-Dah (Zhang et al., 1996) antibodies were performed on formaldehyde-fixed hand-devitellinized embryos, as described above. Secondary antirabbit antibodies, tagged with Cy-5 (Molecular Probes, Inc.), Alexa Fluor® 488 antirat (Molecular Probes, Inc.), and Alexa Fluor® 594 antimouse (Molecular Probes, Inc.) were applied to the embryos as described previously (Karr and Alberts, 1986).
Live embryo analysis
GFP-Nuf embryos were prepared for microinjection and time-lapse scanning confocal microscopy according to Tram et al. (2001). Rhodamine-conjugated tubulin (Molecular Probes, Inc.) was injected at 50% egg length to view microtubule structures.
Microscopy
Microscopy was performed using an inverted photoscope (DMIRB; Leitz) equipped with a laser confocal imaging system (TCS NT; Leica) and an inverted spinning disk confocal microscope (Eclipse TE200; Nikon). UltraVIEW confocal system CSU10 software (PerkinElmer) was used for the image processing (Wojcik et al., 2001).
Cell culture, transfection, and pull-down assays
Pull-down assays using CHO cells expressing GFP-tagged Nuf and GST-Rab fusion proteins were performed as described by Hickson et al. (2003). The GST-Rab5 vector was provided by Francis Barr.
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Acknowledgments |
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G.R.X. Hickson thanks Diabetes UK and the Wellcome Trust for Ph.D. studentships. This work was supported by grants to W. Sullivan from the National Institutes of Health (GM58903); T.S. Hays from the National Institutes of Health (GM44757); and G.W. Gould from the Biotechnology and Biological Sciences Research Council (17/C13723 and 17/REI18423).
Submitted: 23 May 2003
Accepted: 6 August 2003
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References |
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---|
Bajno, L., X.R. Peng, A.D. Schreiber, H.P. Moore, W.S. Trimble, and S. Grinstein. 2000. Focal exocytosis of VAMP3-containing vesicles at sites of phagosome formation. J. Cell Biol. 149:697706.
Bednarek, S.Y., and T.G. Falbel. 2002. Membrane trafficking during plant cytokinesis. Traffic. 3:621629.[CrossRef][Medline]
Bieliavsky, N., M. Geuskens, M. Goldfinger, and R. Tencer. 1992. Isolation of plasma membranes, Golgi bodies and mitochondria of Xenopus laevis morulae. Identification of plasma membrane proteins. J. Submicrosc. Cytol. Pathol. 24:335349.[Medline]
Bluemink, J., and S.W. de Laat. 1973. New membrane formation during cytokinesis in normal and cytochalasin B treated eggs of Xenopus laevis. J. Cell Biol. 59:89108.
Bretscher, M.S. 1996. Getting membrane flow and the cytoskeleton to cooperate in moving cells. Cell. 87:601606.[Medline]
Burgess, R.W., D.L. Deitcher, and T.L. Schwarz. 1997. The synaptic protein syntaxin1 is required for cellularization of Drosophila embryos. J. Cell Biol. 138:861875.
Byers, T.J., and P.B. Armstrong. 1986. Membrane protein redistribution during Xenopus first cleavage. J. Cell Biol. 102:21762184.[Abstract]
Conner, S.D., and G.M. Wessel. 1999. Syntaxin is required for cell division. Mol. Biol. Cell. 10:27352743.
Dollar, G., E. Struckhoff, J. Michaud, and R.S. Cohen. 2002. Rab11 polarization of the Drosophila oocyte: a novel link between membrane trafficking, microtubule organization, and oskar mRNA localization and translation. Development. 129:517526.[Medline]
Donaldson, J.G. 2002. Arf6 and its role in cytoskeletal modulation. Methods Mol. Biol. 189:191198.[Medline]
Dornan, S., A.P. Jackson, and N.J. Gay. 1997. Alpha-adaptin, a marker for endocytosis, is expressed in complex patterns during Drosophila development. Mol. Biol. Cell. 8:13911403.[Abstract]
Field, C., R. Li, and K. Oegema. 1999. Cytokinesis in eukaryotes: a mechanistic comparison. Curr. Opin. Cell Biol. 11:6880.[CrossRef][Medline]
Finger, F.P., and J.G. White. 2002. Fusion and fission: membrane trafficking in animal cytokinesis. Cell. 108:727730.[Medline]
Fishkind, D.J., and Y.L. Wang. 1995. New horizons for cytokinesis. Curr. Opin. Cell Biol. 7:2331.[CrossRef][Medline]
Foe, V.E., and B.M. Alberts. 1983. Studies of nuclear and cytoplasmic behaviour during the five mitotic cycles that precede gastrulation in Drosophila embryogenesis. J. Cell Sci. 61:3170.[Abstract]
Fullilove, S.L., and A.G. Jacobson. 1971. Nuclear elongation and cytokinesis in Drosophila montana. Dev. Biol. 26:560577.[Medline]
Glotzer, M. 2001. Animal cell cytokinesis. Annu. Rev. Cell Dev. Biol. 17:351386.[CrossRef][Medline]
Hackam, D.J., O.D. Rotstein, C. Sjolin, A.D. Schreiber, W.S. Trimble, and S. Grinstein. 1998. v-SNARE-dependent secretion is required for phagocytosis. Proc. Natl. Acad. Sci. USA. 95:1169111696.
Hales, C.M., R. Griner, K.C. Hobdy-Henderson, M.C. Dorn, D. Hardy, R. Kumar, J. Navarre, E.K. Chan, L.A. Lapierre, and J.R. Goldenring. 2001. Identification and characterization of a family of Rab11-interacting proteins. J. Biol. Chem. 276:3906739075.
Hickson, G.R., J. Matheson, B. Riggs, V.H. Maier, A.B. Fielding, R. Prekeris, W. Sullivan, F.A. Barr, and G.W. Gould. 2003. Arfophilins are dual arf/rab 11 binding proteins that regulate recycling endosome distribution and are related to Drosophila nuclear fallout. Mol. Biol. Cell. 14:29082920.
Jankovics, F., R. Sinka, and M. Erdelyi. 2001. An interaction type of genetic screen reveals a role of the Rab11 gene in oskar mRNA localization in the developing Drosophila melanogaster oocyte. Genetics. 158:11771188.
Jantsch-Plunger, V., and M. Glotzer. 1999. Depletion of syntaxins in the early Caenorhabditis elegans embryo reveals a role for membrane fusion events in cytokinesis. Curr. Biol. 9:738745.[CrossRef][Medline]
Kalt, M.R. 1971. The relationship between cleavage and blastocoel formation in Xenopus laevis. I. Light microscopic observations. J. Embryol. Exp. Morphol. 26:3749.[Medline]
Karr, T.L., and B.M. Alberts. 1986. Organization of the cytoskeleton in early Drosophila embryos. J. Cell Biol. 102:14941509.[Abstract]
Kellogg, D.R., T.J. Mitchison, and B.M. Alberts. 1988. Behaviour of microtubules and actin filaments in living Drosophila embryos. Development. 103:675686.[Abstract]
Leaf, D.S., S.J. Roberts, J.C. Gerhart, and H.P. Moore. 1990. The secretory pathway is blocked between the trans-Golgi and the plasma membrane during meiotic maturation in Xenopus oocytes. Dev. Biol. 141:112.[Medline]
Lecuit, T., and E. Wieschaus. 2000. Polarized insertion of new membrane from a cytoplasmic reservoir during cleavage of the Drosophila embryo. J. Cell Biol. 150:849860.
Lindsley, D.L., and G.G. Zimm. 1992. The Genome of Drosophila melanogaster. Academic Press, San Diego, CA. 1134 pp.
Mammoto, A., T. Ohtsuka, I. Hotta, T. Sasaki, and Y. Takai. 1999. Rab11BP/Rabphilin-11, a downstream target of rab11 small G protein implicated in vesicle recycling. J. Biol. Chem. 274:2551725524.
Megraw, T.L., K. Li, L.R. Kao, and T.C. Kaufman. 1999. The centrosomin protein is required for centrosome assembly and function during cleavage in Drosophila. Development. 126:28292839.
Mellman, I. 1996. Endocytosis and molecular sorting. Annu. Rev. Cell Dev. Biol. 12:575625.[CrossRef][Medline]
Mellman, I. 2000. Quo vadis: polarized membrane recycling in motility and phagocytosis. J. Cell Biol. 149:529530.
Mermall, V., and K.G. Miller. 1995. The 95F unconventional myosin is required for proper organization of the Drosophila syncytial blastoderm. J. Cell Biol. 129:15751588.[Abstract]
Mermall, V., J.G. McNally, and K.G. Miller. 1994. Transport of cytoplasmic particles catalysed by an unconventional myosin in living Drosophila embryos. Nature. 369:560562.[CrossRef][Medline]
Miller, K.G., and D.P. Kiehart. 1995. Fly division. J. Cell Biol. 131:15.[Medline]
Prekeris, R., J.M. Davies, and R.H. Scheller. 2001. Identification of a novel Rab11/25 binding domain present in Eferin and Rip proteins. J. Biol. Chem. 276:3896638970.
Radhakrishna, H., R.D. Klausner, and J.G. Donaldson. 1996. Aluminum fluoride stimulates surface protrusions in cells overexpressing the ARF6 GTPase. J. Cell Biol. 134:935947.[Abstract]
Radhakrishna, H., O. Al-Awar, Z. Khachikian, and J.G. Donaldson. 1999. ARF6 requirement for Rac ruffling suggests a role for membrane trafficking in cortical actin rearrangements. J. Cell Sci. 112:855866.
Ren, M., G. Xu, J. Zeng, C. De Lemos-Chiarandini, M. Adesnik, and D.D. Sabatini. 1998. Hydrolysis of GTP on rab11 is required for the direct delivery of transferrin from the pericentriolar recycling compartment to the cell surface but not from sorting endosomes. Proc. Natl. Acad. Sci. USA. 95:61876192.
Robinson, D.N., and J.A. Spudich. 2000. Towards a molecular understanding of cytokinesis. Trends Cell Biol. 10:228237.[CrossRef][Medline]
Rothwell, W.F., and W. Sullivan. 2000. Fluorescent analysis of Drosophila embryos. Drosophila Protocols. W. Sullivan, M. Ashburner, and R.S. Hawley, editors. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. 141157.
Rothwell, W.F., P. Fogarty, C.M. Field, and W. Sullivan. 1998. Nuclear-fallout, a Drosophila protein that cycles from the cytoplasm to the centrosomes, regulates cortical microfilament organization. Development. 125:12951303.
Rothwell, W.F., C.X. Zhang, C. Zelano, T.S. Hsieh, and W. Sullivan. 1999. The Drosophila centrosomal protein Nuf is required for recruiting Dah, a membrane associated protein, to furrows in the early embryo. J. Cell Sci. 112:28852893.
Sanders, E.J. 1975. Aspects of furrow membrane formation in the cleaving Drosophila embryo. Cell Tissue Res. 156:463474.[Medline]
Schejter, E.D., and E. Wieschaus. 1993. Functional elements of the cytoskeleton in the early Drosophila embryo. Annu. Rev. Cell Biol. 9:6799.[Medline]
Scholey, J.M., I. Brust-Mascher, and A. Mogilner. 2003. Cell division. Nature. 422:746752.[CrossRef][Medline]
Segev, N. 2001. Ypt/rab gtpases: regulators of protein trafficking. Sci. STKE. 2001:RE11.
Serano, T.L., H.K. Cheung, L.H. Frank, and R.S. Cohen. 1994. P element transformation vectors for studying Drosophila melanogaster oogenesis and early embryogenesis. Gene. 138:181186.[CrossRef][Medline]
Sheff, D., L. Pelletier, C.B. O'Connell, G. Warren, and I. Mellman. 2002. Transferrin receptor recycling in the absence of perinuclear recycling endosomes. J. Cell Biol. 156:797804.
Sisson, J.C., C. Field, R. Ventura, A. Royou, and W. Sullivan. 2000. Lava lamp, a novel peripheral Golgi protein, is required for Drosophila melanogaster cellularization. J. Cell Biol. 151:905918.
Skop, A.R., D. Bergmann, W.A. Mohler, and J.G. White. 2001. Completion of cytokinesis in C. elegans requires a brefeldin A-sensitive membrane accumulation at the cleavage furrow apex. Curr. Biol. 11:735746.[CrossRef][Medline]
Song, J., Z. Khachikian, H. Radhakrishna, and J.G. Donaldson. 1998. Localization of endogenous ARF6 to sites of cortical actin rearrangement and involvement of ARF6 in cell spreading. J. Cell Sci. 111:22572267.
Sonnichsen, B., S. De Renzis, E. Nielsen, J. Rietdorf, and M. Zerial. 2000. Distinct membrane domains on endosomes in the recycling pathway visualized by multicolor imaging of Rab4, Rab5, and Rab11. J. Cell Biol. 149:901914.
Spradling, A.C., and G.M. Rubin. 1982. Transposition of cloned P elements into Drosophila germ line chromosomes. Science. 218:341347.[Medline]
Stevenson, V., A. Hudson, L. Cooley, and W.E. Theurkauf. 2002. Arp2/3-dependent pseudocleavage [correction of pseudocleavage] furrow assembly in syncytial Drosophila embryos. Curr. Biol. 12:705711.[CrossRef][Medline]
Sullivan, W., and S. Pimpinelli. 1986. The genetic factors altered in homozygous abo stocks of Drosophila melanogaster. Genetics. 114:885895.
Sullivan, W., and W.E. Theurkauf. 1995. The cytoskeleton and morphogenesis of the early Drosophila embryo. Curr. Opin. Cell Biol. 7:1822.[CrossRef][Medline]
Sullivan, W., J.S. Minden, and B.M. Alberts. 1990. daughterless-abo-like, a Drosophila maternal-effect mutation that exhibits abnormal centrosome separation during the late blastoderm divisions. Development. 110:311323.[Abstract]
Sullivan, W., P. Fogarty, and W. Theurkauf. 1993. Mutations affecting the cytoskeletal organization of syncytial Drosophila embryos. Development. 118:12451254.
Swanson, M.M., and C.A. Poodry. 1981. The shibire ts mutant of Drosophila: A probe for the study of embryonic development. Dev. Biol. 84:465470.
Tram, U., B. Riggs, C. Koyama, A. Debec, and W. Sullivan. 2001. Methods for the study of centrosomes in Drosophila during embryogenesis. Methods Cell Biol. 67:113123.[Medline]
Ullrich, O., S. Reinsch, S. Urbe, M. Zerial, and R.G. Parton. 1996. Rab11 regulates recycling through the pericentriolar recycling endosome. J. Cell Biol. 135:913924.[Abstract]
Wojcik, E., R. Basto, M. Serr, F. Scaerou, R. Karess, and T. Hays. 2001. Kinetochore dynein: its dynamics and role in the transport of the Rough deal checkpoint protein. Nat. Cell Biol. 3:10011007.[CrossRef][Medline]
Woodman, P.G. 2000. Biogenesis of the sorting endosome: the role of Rab5. Traffic. 1:695701.[CrossRef][Medline]
Zerial, M., and H. McBride. 2001. Rab proteins as membrane organizers. Nat. Rev. Mol. Cell Biol. 2:107117.[CrossRef][Medline]
Zhang, C.X., M.P. Lee, A.D. Chen, S.D. Brown, and T. Hsieh. 1996. Isolation and characterization of a Drosophila gene essential for early embryonic development and formation of cortical cleavage furrows. J. Cell Biol. 134:923934.[Abstract]
Zhang, C.X., W.F. Rothwell, W. Sullivan, and T.S. Hsieh. 2000. Discontinuous actin hexagon, a protein essential for cortical furrow formation in Drosophila, is membrane associated and hyperphosphorylated. Mol. Biol. Cell. 11:10111022.
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