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Karbon G, Schuler F, Braun VZ, Eichin F, Haschka M, Drach M, Sotillo R, Geley S, Spierings DC, Tijhuis AE, Foijer F, Villunger A. Chronic spindle assembly checkpoint activation causes myelosuppression and gastrointestinal atrophy. EMBO Rep 2024; 25:2743-2772. [PMID: 38806674 PMCID: PMC11169569 DOI: 10.1038/s44319-024-00160-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/30/2024] Open
Abstract
Interference with microtubule dynamics in mitosis activates the spindle assembly checkpoint (SAC) to prevent chromosome segregation errors. The SAC induces mitotic arrest by inhibiting the anaphase-promoting complex (APC) via the mitotic checkpoint complex (MCC). The MCC component MAD2 neutralizes the critical APC cofactor, CDC20, preventing exit from mitosis. Extended mitotic arrest can promote mitochondrial apoptosis and caspase activation. However, the impact of mitotic cell death on tissue homeostasis in vivo is ill-defined. By conditional MAD2 overexpression, we observe that chronic SAC activation triggers bone marrow aplasia and intestinal atrophy in mice. While myelosuppression can be compensated for, gastrointestinal atrophy is detrimental. Remarkably, deletion of pro-apoptotic Bim/Bcl2l11 prevents gastrointestinal syndrome, while neither loss of Noxa/Pmaip or co-deletion of Bid and Puma/Bbc3 has such a protective effect, identifying BIM as rate-limiting apoptosis effector in mitotic cell death of the gastrointestinal epithelium. In contrast, only overexpression of anti-apoptotic BCL2, but none of the BH3-only protein deficiencies mentioned above, can mitigate myelosuppression. Our findings highlight tissue and cell-type-specific survival dependencies in response to SAC perturbation in vivo.
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Affiliation(s)
- Gerlinde Karbon
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Fabian Schuler
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Vincent Z Braun
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Felix Eichin
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Manuel Haschka
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Mathias Drach
- Dermatology, General Hospital, University Hospital Vienna, Vienna, Austria
| | - Rocio Sotillo
- German Cancer Research Center (DKFZ), Division of Molecular Thoracic Oncology, Heidelberg, Germany
| | - Stephan Geley
- Institute for Pathophysiology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Diana Cj Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, The Netherlands
| | - Andrea E Tijhuis
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, The Netherlands
| | - Floris Foijer
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV, Groningen, The Netherlands
| | - Andreas Villunger
- Institute for Developmental Immunology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090, Vienna, Austria.
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Esposito E, Weidemann DE, Rogers JM, Morton CM, Baybay EK, Chen J, Hauf S. Mitotic checkpoint gene expression is tuned by codon usage bias. EMBO J 2022; 41:e107896. [PMID: 35811551 PMCID: PMC9340482 DOI: 10.15252/embj.2021107896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 11/09/2022] Open
Abstract
The mitotic checkpoint (also called spindle assembly checkpoint, SAC) is a signaling pathway that safeguards proper chromosome segregation. Correct functioning of the SAC depends on adequate protein concentrations and appropriate stoichiometries between SAC proteins. Yet very little is known about the regulation of SAC gene expression. Here, we show in the fission yeast Schizosaccharomyces pombe that a combination of short mRNA half-lives and long protein half-lives supports stable SAC protein levels. For the SAC genes mad2+ and mad3+ , their short mRNA half-lives are caused, in part, by a high frequency of nonoptimal codons. In contrast, mad1+ mRNA has a short half-life despite a higher frequency of optimal codons, and despite the lack of known RNA-destabilizing motifs. Hence, different SAC genes employ different strategies of expression. We further show that Mad1 homodimers form co-translationally, which may necessitate a certain codon usage pattern. Taken together, we propose that the codon usage of SAC genes is fine-tuned to ensure proper SAC function. Our work shines light on gene expression features that promote spindle assembly checkpoint function and suggests that synonymous mutations may weaken the checkpoint.
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Affiliation(s)
- Eric Esposito
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Douglas E Weidemann
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jessie M Rogers
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Claire M Morton
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Erod Keaton Baybay
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Jing Chen
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
| | - Silke Hauf
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA.,Fralin Life Sciences Institute, Virginia Tech, Blacksburg, VA, USA
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