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Bryant L, Sangree A, Clark K, Bhoj E. Histone 3.3-related chromatinopathy: missense variants throughout H3-3A and H3-3B cause a range of functional consequences across species. Hum Genet 2024; 143:497-510. [PMID: 36867246 DOI: 10.1007/s00439-023-02536-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/20/2023] [Indexed: 03/04/2023]
Abstract
There has been considerable recent interest in the role that germline variants in histone genes play in Mendelian syndromes. Specifically, missense variants in H3-3A and H3-3B, which both encode Histone 3.3, were discovered to cause a novel neurodevelopmental disorder, Bryant-Li-Bhoj syndrome. Most of the causative variants are private and scattered throughout the protein, but all seem to have either a gain-of-function or dominant negative effect on protein function. This is highly unusual and not well understood. However, there is extensive literature about the effects of Histone 3.3 mutations in model organisms. Here, we collate the previous data to provide insight into the elusive pathogenesis of missense variants in Histone 3.3.
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Affiliation(s)
- Laura Bryant
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Annabel Sangree
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Kelly Clark
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Elizabeth Bhoj
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
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Small EM, Osley MA. A screen for histone mutations that affect quiescence in S. cerevisiae. FEBS J 2023; 290:3539-3562. [PMID: 36871139 DOI: 10.1111/febs.16759] [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: 08/07/2022] [Revised: 12/15/2022] [Accepted: 02/20/2023] [Indexed: 03/06/2023]
Abstract
Quiescence or G0 is a reversible state in which cells cease division but retain the ability to resume proliferation. Quiescence occurs in all organisms and is essential for stem cell maintenance and tissue renewal. It is also related to chronological lifespan (CLS)-the survival of postmitotic quiescent cells (Q cells) over time-and thus contributes to longevity. Important questions remain regarding the mechanisms that control entry into quiescence, maintenance of quiescence and re-entry of Q cells into the cell cycle. S. cerevisiae has emerged as an excellent organism in which to address these questions because of the ease in which Q cells can be isolated. Following entry into G0, yeast cells remain viable for an extended period and can re-enter the cell cycle when exposed to growth-promoting signals. Histone acetylation is lost during the formation of Q cells and chromatin becomes highly condensed. This unique chromatin landscape regulates quiescence-specific transcriptional repression and has been linked to the formation and maintenance of Q cells. To ask whether other chromatin features regulate quiescence, we conducted two comprehensive screens of histone H3 and H4 mutants and identified mutants that show either altered quiescence entry or CLS. Examination of several quiescence entry mutants found that none of the mutants retain histone acetylation in Q cells but show differences in chromatin condensation. A comparison of H3 and H4 mutants with altered CLS to those with altered quiescence entry found that chromatin plays both overlapping and independent roles in the continuum of the quiescence program.
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Affiliation(s)
- Eric M Small
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Mary Ann Osley
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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Mitra M, Coller HA. Screen time: an unbiased search for histone mutations that affect quiescence and chronological aging. FEBS J 2023. [PMID: 37184984 DOI: 10.1111/febs.16788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 04/03/2023] [Indexed: 05/17/2023]
Abstract
Quiescence, reversible cell cycle arrest, is essential for survival during nutrient limitations and the execution of precise developmental patterns. In yeast, entry into quiescence is associated with a loss of histone acetylation as the chromatin becomes tightly condensed. In this issue, Small and Osley performed an unbiased screen of mutations in histone H3 and H4 amino acids in budding yeast and identified histone residues that are critical for quiescence and chronological lifespan. The results indicate that multiple histone amino acids, likely affecting nucleosome structure and a wide range of chromatin-associated processes, can promote or inhibit quiescence entry. Many of the same histone amino acids are also critical regulators of chronological lifespan.
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Affiliation(s)
- Mithun Mitra
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
- Department of Biological Chemistry, David Geffen School of Medicine, Los Angeles, CA, USA
| | - Hilary A Coller
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
- Department of Biological Chemistry, David Geffen School of Medicine, Los Angeles, CA, USA
- Molecular Biology Institute, University of California, Los Angeles, CA, USA
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Pablo-Kaiser A, Tucker MG, Turner GA, Dilday EG, Olmstead AG, Tackett CL, Duina AA. Dominant effects of the histone mutant H3-L61R on Spt16-gene interactions in budding yeast. Epigenetics 2022; 17:2347-2355. [PMID: 36073733 DOI: 10.1080/15592294.2022.2121073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Recent studies have unveiled an association between an L61R substitution within the human histone H3.3 protein and the presentation of neurodevelopmental disorders in two patients. In both cases, the mutation responsible for this substitution is encoded by one allele of the H3F3A gene and, if this mutation is indeed responsible for the disease phenotypes, it must act in a dominant fashion since the genomes of these patients also harbour three other alleles encoding wild-type histone H3.3. In our previous work in yeast, we have shown that most amino acid substitutions at H3-L61 cause an accumulation of the Spt16 component of the yFACT histone chaperone complex at the 3' end of transcribed genes, a defect we have attributed to impaired yFACT dissociation from chromatin following transcription. In those studies, however, the H3-L61R mutant had not been tested since it does not sustain viability when expressed as the sole source of histone H3 in cells. In the present work, we show that H3-L61R impairs proper Spt16 dissociation from genes when co-expressed with wild-type histone H3 in haploid cells as well as in diploid cells that express the mutant protein from one of four histone H3-encoding alleles. These results, combined with other studies linking loss of function mutations in human Spt16 and neurodevelopmental disorders, provide a possible molecular mechanism underlying the neurodevelopmental disorders seen in patients expressing the histone H3.3 L61R mutant.
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Affiliation(s)
- Alex Pablo-Kaiser
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - McKenzie G Tucker
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - Grace A Turner
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - Elijah G Dilday
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - Avery G Olmstead
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - Caroline L Tackett
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
| | - Andrea A Duina
- Biology and Health Sciences Department, Hendrix College, Conway, Arkansas, USA
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Jeronimo C, Robert F. The histone chaperone FACT: a guardian of chromatin structure integrity. Transcription 2022; 13:16-38. [PMID: 35485711 PMCID: PMC9467567 DOI: 10.1080/21541264.2022.2069995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The identification of FACT as a histone chaperone enabling transcription through chromatin in vitro has strongly shaped how its roles are envisioned. However, FACT has been implicated in essentially all aspects of chromatin biology, from transcription to DNA replication, DNA repair, and chromosome segregation. In this review, we focus on recent literature describing the role and mechanisms of FACT during transcription. We highlight the prime importance of FACT in preserving chromatin integrity during transcription and challenge its role as an elongation factor. We also review evidence for FACT's role as a cell-type/gene-specificregulator of gene expression and briefly summarize current efforts at using FACT inhibition as an anti-cancerstrategy.
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Affiliation(s)
- Célia Jeronimo
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada
| | - François Robert
- Institut de recherches cliniques de Montréal, Montréal, Québec, Canada.,Département de Médecine, Faculté de Médecine, Université de Montréal, Montréal, Québec, Canada.,Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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Campbell JB, Edwards MJ, Ozersky SA, Duina AA. Evidence that dissociation of Spt16 from transcribed genes is partially dependent on RNA Polymerase II termination. Transcription 2019; 10:195-206. [PMID: 31809228 PMCID: PMC6948958 DOI: 10.1080/21541264.2019.1685837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
FACT (FAcilitates Chromatin Transactions) is a highly conserved histone chaperone complex in eukaryotic cells that can interact and manipulate nucleosomes in order to promote a variety of DNA-based processes and to maintain the integrity of chromatin throughout the genome. Whereas key features of the physical interactions that occur between FACT and nucleosomes in vitro have been elucidated in recent years, less is known regarding FACT functional dynamics in vivo. Using the Saccharomyces cerevisiae system, we now provide evidence that at least at some genes dissociation of the FACT subunit Spt16 from their 3′ ends is partially dependent on RNA Polymerase II (Pol II) termination. Combined with other studies, our results are consistent with a two-phase mechanism for FACT dissociation from genes, one that occurs upstream from Pol II dissociation and is Pol II termination-independent and the other that occurs further downstream and is dependent on Pol II termination.
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Affiliation(s)
| | | | | | - Andrea A Duina
- Biology Department, Hendrix College, Conway, Arkansas, USA
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