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Espejo-Serrano C, Aitken C, Tan BF, May DG, Chrisopulos RJ, Roux KJ, Demmers JA, Mackintosh SG, Gribnau J, Bustos F, Gontan C, Findlay GM. Chromatin targeting of the RNF12/RLIM E3 ubiquitin ligase controls transcriptional responses. Life Sci Alliance 2024; 7:e202302282. [PMID: 38199845 PMCID: PMC10781586 DOI: 10.26508/lsa.202302282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Protein ubiquitylation regulates key biological processes including transcription. This is exemplified by the E3 ubiquitin ligase RNF12/RLIM, which controls developmental gene expression by ubiquitylating the REX1 transcription factor and is mutated in an X-linked intellectual disability disorder. However, the precise mechanisms by which ubiquitylation drives specific transcriptional responses are not known. Here, we show that RNF12 is recruited to specific genomic locations via a consensus sequence motif, which enables co-localisation with REX1 substrate at gene promoters. Surprisingly, RNF12 chromatin recruitment is achieved via a non-catalytic basic region and comprises a previously unappreciated N-terminal autoinhibitory mechanism. Furthermore, RNF12 chromatin targeting is critical for REX1 ubiquitylation and downstream RNF12-dependent gene regulation. Our results demonstrate a key role for chromatin in regulation of the RNF12-REX1 axis and provide insight into mechanisms by which protein ubiquitylation enables programming of gene expression.
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Affiliation(s)
- Carmen Espejo-Serrano
- https://ror.org/01zg1tt02 MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Catriona Aitken
- https://ror.org/01zg1tt02 MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Beatrice F Tan
- https://ror.org/018906e22 Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Danielle G May
- https://ror.org/00sfn8y78 Enabling Technologies Group, Sanford Research, Sioux Falls, SD, USA
| | - Rachel J Chrisopulos
- https://ror.org/00sfn8y78 Enabling Technologies Group, Sanford Research, Sioux Falls, SD, USA
| | - Kyle J Roux
- https://ror.org/00sfn8y78 Enabling Technologies Group, Sanford Research, Sioux Falls, SD, USA
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
| | - Jeroen Aa Demmers
- https://ror.org/018906e22 Proteomics Center and Department of Biochemistry, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Joost Gribnau
- https://ror.org/018906e22 Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Francisco Bustos
- Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
- https://ror.org/00sfn8y78 Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, USA
| | - Cristina Gontan
- https://ror.org/018906e22 Department of Developmental Biology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Greg M Findlay
- https://ror.org/01zg1tt02 MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
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Wang F, Chander A, Yoon Y, Welton JM, Wallingford MC, Espejo-Serrano C, Bustos F, Findlay GM, Mager J, Bach I. Roles of the Rlim-Rex1 axis during X chromosome inactivation in mice. Proc Natl Acad Sci U S A 2023; 120:e2313200120. [PMID: 38113263 PMCID: PMC10756295 DOI: 10.1073/pnas.2313200120] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/17/2023] [Indexed: 12/21/2023] Open
Abstract
In female mice, the gene dosage from X chromosomes is adjusted by a process called X chromosome inactivation (XCI) that occurs in two steps. An imprinted form of XCI (iXCI) that silences the paternally inherited X chromosome (Xp) is initiated at the 2- to 4-cell stages. As extraembryonic cells including trophoblasts keep the Xp silenced, epiblast cells that give rise to the embryo proper reactivate the Xp and undergo a random form of XCI (rXCI) around implantation. Both iXCI and rXCI require the lncRNA Xist, which is expressed from the X to be inactivated. The X-linked E3 ubiquitin ligase Rlim (Rnf12) in conjunction with its target protein Rex1 (Zfp42), a critical repressor of Xist, have emerged as major regulators of iXCI. However, their roles in rXCI remain controversial. Investigating early mouse development, we show that the Rlim-Rex1 axis is active in pre-implantation embryos. Upon implantation Rex1 levels are downregulated independently of Rlim specifically in epiblast cells. These results provide a conceptual framework of how the functional dynamics between Rlim and Rex1 ensures regulation of iXCI but not rXCI in female mice.
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Affiliation(s)
- Feng Wang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Ashmita Chander
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA01003
| | - Yeonsoo Yoon
- Division of Genes and Development, Department of Pediatrics, University of Massachusetts Chan Medical School, Worcester, MA01605
| | - Janelle M. Welton
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA01003
| | - Mary C. Wallingford
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA01003
| | - Carmen Espejo-Serrano
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, DundeeDD1 5EH, United Kingdom
| | - Francisco Bustos
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, DundeeDD1 5EH, United Kingdom
| | - Greg M. Findlay
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, DundeeDD1 5EH, United Kingdom
| | - Jesse Mager
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA01003
| | - Ingolf Bach
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA01605
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Bustos F, Mathur S, Espejo-Serrano C, Toth R, Hastie CJ, Virdee S, Findlay GM. Activity-based probe profiling of RNF12 E3 ubiquitin ligase function in Tonne-Kalscheuer syndrome. Life Sci Alliance 2022; 5:5/11/e202101248. [PMID: 35764390 PMCID: PMC9240097 DOI: 10.26508/lsa.202101248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 06/08/2022] [Accepted: 06/08/2022] [Indexed: 11/24/2022] Open
Abstract
Ubiquitylation enzymes are involved in all aspects of eukaryotic biology and are frequently disrupted in disease. One example is the E3 ubiquitin ligase RNF12/RLIM, which is mutated in the developmental disorder Tønne-Kalscheuer syndrome (TOKAS). RNF12 TOKAS variants largely disrupt catalytic E3 ubiquitin ligase activity, which presents a pressing need to develop approaches to assess the impact of variants on RNF12 activity in patients. Here, we use photocrosslinking activity-based probes (photoABPs) to monitor RNF12 RING E3 ubiquitin ligase activity in normal and pathogenic contexts. We demonstrate that photoABPs undergo UV-induced labelling of RNF12 that is consistent with its RING E3 ligase activity. Furthermore, photoABPs robustly report the impact of RNF12 TOKAS variants on E3 activity, including variants within the RING domain and distal non-RING regulatory elements. Finally, we show that this technology can be rapidly deployed in human pluripotent stem cells. In summary, photoABPs are versatile tools that can directly identify disruptions to RING E3 ubiquitin ligase activity in human disease, thereby providing new insight into pathogenic mechanisms.
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Affiliation(s)
- Francisco Bustos
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Sunil Mathur
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Carmen Espejo-Serrano
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Rachel Toth
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - C James Hastie
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Satpal Virdee
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Greg M Findlay
- Medical Research Council (MRC) Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
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Segarra-Fas A, Espejo-Serrano C, Bustos F, Zhou H, Wang F, Toth R, Macartney T, Bach I, Nardocci G, Findlay GM. An RNF12-USP26 amplification loop drives germ cell specification and is disrupted by disease-associated mutations. Sci Signal 2022; 15:eabm5995. [PMID: 35857630 PMCID: PMC7613676 DOI: 10.1126/scisignal.abm5995] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The E3 ubiquitin ligase RNF12 plays essential roles during development, and the gene encoding it, RLIM, is mutated in the X-linked human developmental disorder Tonne-Kalscheuer syndrome (TOKAS). Substrates of RNF12 include transcriptional regulators such as the pluripotency-associated transcriptional repressor REX1. Using global quantitative proteomics in male mouse embryonic stem cells, we identified the deubiquitylase USP26 as a putative downstream target of RNF12 activity. RNF12 relieved REX1-mediated repression of Usp26, leading to an increase in USP26 abundance and the formation of RNF12-USP26 complexes. Interaction with USP26 prevented RNF12 autoubiquitylation and proteasomal degradation, thereby establishing a transcriptional feed-forward loop that amplified RNF12-dependent derepression of REX1 targets. We showed that the RNF12-USP26 axis operated specifically in mouse testes and was required for the expression of gametogenesis genes and for germ cell differentiation in vitro. Furthermore, this RNF12-USP26 axis was disrupted by RLIM and USP26 variants found in TOKAS and infertility patients, respectively. This work reveals synergy within the ubiquitylation cycle that controls a key developmental process in gametogenesis and that is disrupted in human genetic disorders.
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Affiliation(s)
- Anna Segarra-Fas
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Carmen Espejo-Serrano
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Francisco Bustos
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Houjiang Zhou
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Feng Wang
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Rachel Toth
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Thomas Macartney
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
| | - Ingolf Bach
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Gino Nardocci
- School of Medicine, Faculty of Medicine, Universidad de los Andes, Santiago, Chile
- Program in Molecular Biology and Bioinformatics, Center for Biomedical Research and Innovation (CIIB), Universidad de los Andes, Santiago, Chile
- IMPACT, Center of Interventional Medicine for Precision and Advanced Cellular Therapy, Santiago, Chile
| | - Greg M. Findlay
- The MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, The University of Dundee, Dundee DD1 5EH, UK
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Bustos F, Espejo-Serrano C, Segarra-Fas A, Toth R, Eaton AJ, Kernohan KD, Wilson MJ, Riley LG, Findlay GM. A novel RLIM/RNF12 variant disrupts protein stability and function to cause severe Tonne-Kalscheuer syndrome. Sci Rep 2021; 11:9560. [PMID: 33953269 PMCID: PMC8100121 DOI: 10.1038/s41598-021-88911-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 04/19/2021] [Indexed: 11/16/2022] Open
Abstract
Tonne-Kalscheuer syndrome (TOKAS) is an X-linked intellectual disability syndrome associated with variable clinical features including craniofacial abnormalities, hypogenitalism and diaphragmatic hernia. TOKAS is caused exclusively by variants in the gene encoding the E3 ubiquitin ligase gene RLIM, also known as RNF12. Here we report identification of a novel RLIM missense variant, c.1262A>G p.(Tyr421Cys) adjacent to the regulatory basic region, which causes a severe form of TOKAS resulting in perinatal lethality by diaphragmatic hernia. Inheritance and X-chromosome inactivation patterns implicate RLIM p.(Tyr421Cys) as the likely pathogenic variant in the affected individual and within the kindred. We show that the RLIM p.(Tyr421Cys) variant disrupts both expression and function of the protein in an embryonic stem cell model. RLIM p.(Tyr421Cys) is correctly localised to the nucleus, but is readily degraded by the proteasome. The RLIM p.(Tyr421Cys) variant also displays significantly impaired E3 ubiquitin ligase activity, which interferes with RLIM function in Xist long-non-coding RNA induction that initiates imprinted X-chromosome inactivation. Our data uncover a highly disruptive missense variant in RLIM that causes a severe form of TOKAS, thereby expanding our understanding of the molecular and phenotypic spectrum of disease severity.
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Affiliation(s)
- Francisco Bustos
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Carmen Espejo-Serrano
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Anna Segarra-Fas
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Rachel Toth
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK
| | - Alison J Eaton
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Kristin D Kernohan
- Newborn Screening Ontario, Children's Hospital of Eastern Ontario, Ottawa, Canada
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - Meredith J Wilson
- Department of Clinical Genetics, The Children's Hospital at Westmead, Sydney, Australia
- Discipline of Genomic Medicine, University of Sydney, Sydney, Australia
| | - Lisa G Riley
- Rare Diseases Functional Genomics, Kids Research, The Children's Hospital at Westmead and The Children's Medical Research Institute, Sydney, Australia.
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia.
| | - Greg M Findlay
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, UK.
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