dictyNews

Electronic Edition

Volume 49, number 12

May 12, 2023



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Abstracts

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Temporal changes of nuclear envelope permeability during 

semi-closed mitosis in Dictyostelium amoebae



Kristina Mitic, Irene Meyer, Ralph Gräf and Marianne Grafe*



Department of Cell Biology, University of Potsdam, 

Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany





Cells, in press



The Amoebozoan Dictyostelium discoideum, exhibits a semi-closed 

mitosis, in which the nuclear membranes remain intact but become 

permeabilized to allow access of tubulin and spindle assembly 

factors to the nuclear interior. Previous work indicated that 

this is accomplished at least by a partial disassembly of nuclear 

pore complexes (NPCs). Further contributions by the insertion 

process of the duplicating, formerly cytosolic centrosome into 

the nuclear envelope and nuclear envelope fenestrations forming 

around the central spindle during karyokinesis were discussed. 

We studied the behavior of several Dictyostelium nuclear envelope, 

centrosomal and nuclear pore complex (NPC) components tagged 

with fluorescence markers together with a nuclear permeabilization 

marker (NLS-TdTomato) by live cell imaging. We could show that 

permeabilization of the nuclear envelope during mitosis occurs in 

synchrony with centrosome insertion into the nuclear envelope and 

partial disassembly of nuclear pore complexes. Furthermore, 

centrosome duplication takes place after its insertion into the 

nuclear envelope and after initiation of permeabilization. Restoration 

of nuclear envelope integrity usually occurs long after re-assembly 

of NPCs and cytokinesis has taken place and is accompanied by a 

concentration of endosomal sorting complex required for transport 

(ESCRT) components at both sites of nuclear envelope fenestration 

(centrosome and central spindle)..





Submitted by Ralph Gräf [[log in to unmask]]

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[End dictyNews, volume 49, number 12]