The midbody ring scaffolds the abscission machinery in the absence of midbody microtubules.
Abscission completes cytokinesis to form the two daughter cells. Although abscission could be organized from the inside out by the microtubule-based midbody or from the outside in by the contractile ring-derived midbody ring, it is assumed that midbody microtubules scaffold the abscission machinery. In this paper, we assess the contribution of midbody microtubules versus the midbody ring in the Caenorhabditis elegans embryo. We show that abscission occurs in two stages. First, the cytoplasm in the daughter cells becomes isolated, coincident with formation of the intercellular bridge; proper progression through this stage required the septins (a midbody ring component) but not the membrane-remodeling endosomal sorting complex required for transport (ESCRT) machinery. Second, the midbody and midbody ring are released into a specific daughter cell during the subsequent cell division; this stage required the septins and the ESCRT machinery. Surprisingly, midbody microtubules were dispensable for both stages. These results delineate distinct steps during abscission and highlight the central role of the midbody ring, rather than midbody microtubules, in their execution.
Department of Cellular and Molecular Medicine, Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093.
Rebecca A
RA
Green
Jonathan R
JR
Mayers
Shaohe
S
Wang
Lindsay
L
Lewellyn
Arshad
A
Desai
Anjon
A
Audhya
Karen
K
Oegema
D008841:Actin Cytoskeleton; D000818:Animals; D064107:Aurora Kinase B / Q000378:metabolism; D017173:Caenorhabditis elegans / Q000196:embryology*; D002455:Cell Division / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane; D003285:Contractile Proteins; D048749:Cytokinesis / Q000235:genetics*; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000235:genetics; D008938:Mitosis; D024462:Myosin Type II; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D058112:Septins / Q000235:genetics / Q000378:metabolism
D003285:Contractile Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D063146:Polycomb-Group Proteins; D034741:RNA, Small Interfering; D064107:Aurora Kinase B; D024462:Myosin Type II; D058112:Septins