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Botta S, de Prisco N, Chemiakine A, Brandt V, Cabaj M, Patel P, Doron-Mandel E, Treadway CJ, Jovanovic M, Brown NG, Soni RK, Gennarino VA. Dosage sensitivity to Pumilio1 variants in the mouse brain reflects distinct molecular mechanisms. EMBO J 2023:e112721. [PMID: 37070548 DOI: 10.15252/embj.2022112721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 03/01/2023] [Accepted: 03/14/2023] [Indexed: 04/19/2023] Open
Abstract
Different mutations in the RNA-binding protein Pumilio1 (PUM1) cause divergent phenotypes whose severity tracks with dosage: a mutation that reduces PUM1 levels by 25% causes late-onset ataxia, whereas haploinsufficiency causes developmental delay and seizures. Yet PUM1 targets are derepressed to equal degrees in both cases, and the more severe mutation does not hinder PUM1's RNA-binding ability. We therefore considered the possibility that the severe mutation might disrupt PUM1 interactions, and identified PUM1 interactors in the murine brain. We find that mild PUM1 loss derepresses PUM1-specific targets, but the severe mutation disrupts interactions with several RNA-binding proteins and the regulation of their targets. In patient-derived cell lines, restoring PUM1 levels restores these interactors and their targets to normal levels. Our results demonstrate that dosage sensitivity does not always signify a linear relationship with protein abundance but can involve distinct mechanisms. We propose that to understand the functions of RNA-binding proteins in a physiological context will require studying their interactions as well as their targets.
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Affiliation(s)
- Salvatore Botta
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
- Department of Translational Medical Science, University of Campania Luigi Vanvitelli, Caserta, Italy
| | - Nicola de Prisco
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Alexei Chemiakine
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Vicky Brandt
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Maximilian Cabaj
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Purvi Patel
- Proteomics and Macromolecular Crystallography Shared Resource, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Ella Doron-Mandel
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Colton J Treadway
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Nicholas G Brown
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Rajesh K Soni
- Proteomics and Macromolecular Crystallography Shared Resource, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Vincenzo A Gennarino
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
- Departments of Neurology, Columbia University Irving Medical Center, New York, NY, USA
- Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY, USA
- Initiative for Columbia Ataxia and Tremor, Columbia University Irving Medical Center, New York, NY, USA
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