Furrow-specific endocytosis during cytokinesis of zebrafish blastomeres.
Mutations affecting endocytosis, such as those in clathrin and dynamin, unexpectedly cause defects in cytokinesis in a number of organisms. To explore the relationship between endocytosis and cytokinesis, we used the relatively large cells of the transparent zebrafish embryo. Using fluorescent markers for fluid-phase as well as plasma membrane uptake, we demonstrate that cytokinesis involves furrow-specific endocytosis. Clathrin-coated pits are visible near the furrow in ultrathin sections, while immunolabeling demonstrates that clathrin and caveolin are localized to the cleavage furrow. Hence, it is likely that both clathrin- and caveolae-mediated endocytosis occurs at the furrow during cytokinesis. Dynamin II is also localized to the furrow and may mediate furrow-specific endocytosis. Treatment of embryos with chlorpromazine or with methyl-beta-cyclodextrin, both of which inhibit endocytosis, prevents the normal completion of cytokinesis. These data suggest that furrow-specific endocytosis is an integral part of cytokinesis.
Feng
Bo
B
Laboratory of Fish Developmental Genetics, Institute of Molecular Agrobiology, National University of Singapore, 1 Research Link, NUS, 117604, Singapore.
Schwarz
Heinz
H
Jesuthasan
Suresh
S
D000818:Animals; D001757:Blastomeres / Q000737:chemistry / Q000166:cytology* / Q000648:ultrastructure; D051242:Caveolin 1; D022461:Caveolins / Q000032:analysis; D002455:Cell Division / Q000187:drug effects; D002746:Chlorpromazine / Q000494:pharmacology; D002966:Clathrin / Q000032:analysis; D003505:Cyclodextrins / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D005089:Exocytosis; D008856:Microscopy, Fluorescence; D022161:Transport Vesicles / Q000378:metabolism; D015027:Zebrafish / Q000033:anatomy & histology / Q000196:embryology*; D047392:beta-Cyclodextrins
D051242:Caveolin 1; D022461:Caveolins; D002966:Clathrin; D003505:Cyclodextrins; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D002746:Chlorpromazine