1. Cytoplasmic division cycles without the nucleus and mitotic CDK/cyclin complexes
- Author
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Bakshi, Anand, Iturra, Fabio Echegaray, Alamban, Andrew, Rosas-Salvans, Miquel, Dumont, Sophie, and Aydogan, Mustafa G
- Subjects
Biological Sciences ,1.1 Normal biological development and functioning ,Underpinning research ,Generic health relevance ,Animals ,Cell Nucleus ,Centrosome ,Cyclins ,Cytokinesis ,Drosophila ,Mitosis ,Spindle Apparatus ,Embryo ,Nonmammalian ,Cdk ,Drosophila embryo ,autonomous clocks ,cell cycle ,centrosome ,cyclin ,cytokinesis ,epithelial homeostasis ,microtubules ,mitosis ,Medical and Health Sciences ,Developmental Biology ,Biological sciences ,Biomedical and clinical sciences - Abstract
Cytoplasmic divisions are thought to rely on nuclear divisions and mitotic signals. We demonstrate in Drosophila embryos that cytoplasm can divide repeatedly without nuclei and mitotic CDK/cyclin complexes. Cdk1 normally slows an otherwise faster cytoplasmic division cycle, coupling it with nuclear divisions, and when uncoupled, cytoplasm starts dividing before mitosis. In developing embryos where CDK/cyclin activity can license mitotic microtubule (MT) organizers like the spindle, cytoplasmic divisions can occur without the centrosome, a principal organizer of interphase MTs. However, centrosomes become essential in the absence of CDK/cyclin activity, implying that the cytoplasm can employ either the centrosome-based interphase or CDK/cyclin-dependent mitotic MTs to facilitate its divisions. Finally, we present evidence that autonomous cytoplasmic divisions occur during unperturbed fly embryogenesis and that they may help extrude mitotically stalled nuclei during blastoderm formation. We postulate that cytoplasmic divisions occur in cycles governed by a yet-to-be-uncovered clock mechanism autonomous from CDK/cyclin complexes.
- Published
- 2023