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Mellis IA, Melzer ME, Bodkin N, Goyal Y. Prevalence of and gene regulatory constraints on transcriptional adaptation in single cells. Genome Biol 2024; 25:217. [PMID: 39135102 PMCID: PMC11320884 DOI: 10.1186/s13059-024-03351-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 07/25/2024] [Indexed: 08/15/2024] Open
Abstract
BACKGROUND Cells and tissues have a remarkable ability to adapt to genetic perturbations via a variety of molecular mechanisms. Nonsense-induced transcriptional compensation, a form of transcriptional adaptation, has recently emerged as one such mechanism, in which nonsense mutations in a gene trigger upregulation of related genes, possibly conferring robustness at cellular and organismal levels. However, beyond a handful of developmental contexts and curated sets of genes, no comprehensive genome-wide investigation of this behavior has been undertaken for mammalian cell types and conditions. How the regulatory-level effects of inherently stochastic compensatory gene networks contribute to phenotypic penetrance in single cells remains unclear. RESULTS We analyze existing bulk and single-cell transcriptomic datasets to uncover the prevalence of transcriptional adaptation in mammalian systems across diverse contexts and cell types. We perform regulon gene expression analyses of transcription factor target sets in both bulk and pooled single-cell genetic perturbation datasets. Our results reveal greater robustness in expression of regulons of transcription factors exhibiting transcriptional adaptation compared to those of transcription factors that do not. Stochastic mathematical modeling of minimal compensatory gene networks qualitatively recapitulates several aspects of transcriptional adaptation, including paralog upregulation and robustness to mutation. Combined with machine learning analysis of network features of interest, our framework offers potential explanations for which regulatory steps are most important for transcriptional adaptation. CONCLUSIONS Our integrative approach identifies several putative hits-genes demonstrating possible transcriptional adaptation-to follow-up on experimentally and provides a formal quantitative framework to test and refine models of transcriptional adaptation.
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Affiliation(s)
- Ian A Mellis
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
| | - Madeline E Melzer
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Nicholas Bodkin
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yogesh Goyal
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA.
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
- CZ Biohub Chicago, LLC, Chicago, IL, USA.
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Poyatos JF. Design principles of multi-map variation in biological systems. Phys Biol 2024; 21:043001. [PMID: 38949447 DOI: 10.1088/1478-3975/ad5d6c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 07/01/2024] [Indexed: 07/02/2024]
Abstract
Complexity in biology is often described using a multi-map hierarchical architecture, where the genotype, representing the encoded information, is mapped to the functional level, known as the phenotype, which is then connected to a latent phenotype we refer to as fitness. This underlying architecture governs the processes driving evolution. Furthermore, natural selection, along with other neutral forces, can, in turn, modify these maps. At each level, variation is observed. Here, I propose the need to establish principles that can aid in understanding the transformation of variation within this multi-map architecture. Specifically, I will introduce three, related to the presence of modulators, constraints, and the modular channeling of variation. By comprehending these design principles in various biological systems, we can gain better insights into the mechanisms underlying these maps and how they ultimately contribute to evolutionary dynamics.
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Affiliation(s)
- Juan F Poyatos
- Logic of Genomic Systems Lab (CNB-CSIC), Madrid 28049, Spain
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Vande Zande P, Siddiq MA, Hodgins-Davis A, Kim L, Wittkopp PJ. Active compensation for changes in TDH3 expression mediated by direct regulators of TDH3 in Saccharomyces cerevisiae. PLoS Genet 2023; 19:e1011078. [PMID: 38091349 PMCID: PMC10752532 DOI: 10.1371/journal.pgen.1011078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/27/2023] [Accepted: 11/22/2023] [Indexed: 12/26/2023] Open
Abstract
Genetic networks are surprisingly robust to perturbations caused by new mutations. This robustness is conferred in part by compensation for loss of a gene's activity by genes with overlapping functions, such as paralogs. Compensation occurs passively when the normal activity of one paralog can compensate for the loss of the other, or actively when a change in one paralog's expression, localization, or activity is required to compensate for loss of the other. The mechanisms of active compensation remain poorly understood in most cases. Here we investigate active compensation for the loss or reduction in expression of the Saccharomyces cerevisiae gene TDH3 by its paralog TDH2. TDH2 is upregulated in a dose-dependent manner in response to reductions in TDH3 by a mechanism requiring the shared transcriptional regulators Gcr1p and Rap1p. TDH1, a second and more distantly related paralog of TDH3, has diverged in its regulation and is upregulated by another mechanism. Other glycolytic genes regulated by Rap1p and Gcr1p show changes in expression similar to TDH2, suggesting that the active compensation by TDH3 paralogs is part of a broader homeostatic response mediated by shared transcriptional regulators.
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Affiliation(s)
- Pétra Vande Zande
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mohammad A. Siddiq
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrea Hodgins-Davis
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lisa Kim
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Patricia J. Wittkopp
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, United States of America
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Mellis IA, Bodkin N, Melzer ME, Goyal Y. Prevalence of and gene regulatory constraints on transcriptional adaptation in single cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553318. [PMID: 37645989 PMCID: PMC10462021 DOI: 10.1101/2023.08.14.553318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Cells and tissues have a remarkable ability to adapt to genetic perturbations via a variety of molecular mechanisms. Nonsense-induced transcriptional compensation, a form of transcriptional adaptation, has recently emerged as one such mechanism, in which nonsense mutations in a gene can trigger upregulation of related genes, possibly conferring robustness at cellular and organismal levels. However, beyond a handful of developmental contexts and curated sets of genes, to date, no comprehensive genome-wide investigation of this behavior has been undertaken for mammalian cell types and contexts. Moreover, how the regulatory-level effects of inherently stochastic compensatory gene networks contribute to phenotypic penetrance in single cells remains unclear. Here we combine computational analysis of existing datasets with stochastic mathematical modeling and machine learning to uncover the widespread prevalence of transcriptional adaptation in mammalian systems and the diverse single-cell manifestations of minimal compensatory gene networks. Regulon gene expression analysis of a pooled single-cell genetic perturbation dataset recapitulates important model predictions. Our integrative approach uncovers several putative hits-genes demonstrating possible transcriptional adaptation-to follow up on experimentally, and provides a formal quantitative framework to test and refine models of transcriptional adaptation.
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Affiliation(s)
- Ian A. Mellis
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Nicholas Bodkin
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Madeline E. Melzer
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Yogesh Goyal
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Center for Synthetic Biology, Northwestern University, Chicago, IL, USA
- Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Zande PV, Wittkopp PJ. Active compensation for changes in TDH3 expression mediated by direct regulators of TDH3 in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.13.523977. [PMID: 36711763 PMCID: PMC9882118 DOI: 10.1101/2023.01.13.523977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Genetic networks are surprisingly robust to perturbations caused by new mutations. This robustness is conferred in part by compensation for loss of a gene's activity by genes with overlapping functions, such as paralogs. Compensation occurs passively when the normal activity of one paralog can compensate for the loss of the other, or actively when a change in one paralog's expression, localization, or activity is required to compensate for loss of the other. The mechanisms of active compensation remain poorly understood in most cases. Here we investigate active compensation for the loss or reduction in expression of the Saccharomyces cerevisiae gene TDH3 by its paralogs TDH1 and TDH2. TDH1 and TDH2 are upregulated in a dose-dependent manner in response to reductions in TDH3 by a mechanism requiring the shared transcriptional regulators Gcr1p and Rap1p. Other glycolytic genes regulated by Rap1p and Gcr1p show changes in expression similar to TDH2, suggesting that the active compensation by TDH3 paralogs is part of a broader homeostatic response mediated by shared transcriptional regulators.
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Affiliation(s)
- Pétra Vande Zande
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Current address: Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, USA
| | - Patricia J Wittkopp
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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Ámon J, Varga G, Pfeiffer I, Farkas Z, Karácsony Z, Hegedűs Z, Vágvölgyi C, Hamari Z. The role of the Aspergillus nidulans high mobility group B protein HmbA, the orthologue of Saccharomyces cerevisiae Nhp6p. Sci Rep 2022; 12:17334. [PMID: 36243791 PMCID: PMC9569327 DOI: 10.1038/s41598-022-22202-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/11/2022] [Indexed: 01/10/2023] Open
Abstract
The mammalian HMGB1 is a high-mobility-group B protein, which is both an architectural and functional element of chromatin. Nhp6p, the extensively studied fungal homologue of HMGB1 in Saccharomyces cerevisiae has pleiotropic physiological functions. Despite the existence of Nhp6p orthologues in filamentous ascomycetes, little is known about their physiological roles besides their contribution to sexual development. Here we study the function of HmbA, the Aspergillus nidulans orthologue of Nhp6p. We show that HmbA influences the utilization of various carbon- and nitrogen sources, stress tolerance, secondary metabolism, hyphae elongation and maintenance of polarized growth. Additionally, by conducting heterologous expression studies, we demonstrate that HmbA and Nhp6p are partially interchangeable. HmbA restores SNR6 transcription and fitness of nhp6AΔBΔ mutant and reverses its heat sensitivity. Nhp6Ap complements several phenotypes of hmbAΔ, including ascospore formation, utilization of various carbon- and nitrogen-sources, radial growth rate, hypha elongation by polarized growth. However, Nhp6Ap does not complement sterigmatocystin production in a hmbAΔ strain. Finally, we also show that HmbA is necessary for the normal expression of the endochitinase chiA, a cell wall re-modeller that is pivotal for the normal mode of maintenance of polar growth.
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Affiliation(s)
- Judit Ámon
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Gabriella Varga
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ilona Pfeiffer
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Zoltán Farkas
- Synthetic and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Zoltán Karácsony
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Food and Wine Research Institute, Eszterházy Károly University, Eger, Hungary
| | - Zsófia Hegedűs
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Zsuzsanna Hamari
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary.
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Chidambaram R, Ramachandran G, Rajasekharan R, Nachiappan V. Impairment of transcription factor Gcr1p binding motif perturbs OPI3 transcription in Saccharomyces cerevisiae. J Cell Biochem 2022; 123:1032-1052. [PMID: 35416329 DOI: 10.1002/jcb.30245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 03/09/2022] [Accepted: 03/16/2022] [Indexed: 11/08/2022]
Abstract
In Saccharomyces cerevisiae, the transcription factor GCR1 plays a vital role in carbohydrate metabolism and in the current study we tried to elucidate its role in lipid metabolism. In silico analysis revealed the upstream activation sequence (UAS) in the promoter region of OPI3 possessed six conserved recognition sequences for Gcr1p and the ChIP assay confirmed the binding of Gcr1p on the OPI3 promoter region. The real-time quantitative polymerase chain reaction and promoter-reporter activity revealed a substantial reduction in OPI3 expression and was supported with decreased phosphatidylcholine (PC) level that is rescued with exogenous choline supplementation in gcr1∆ cells. Simultaneously, there was an increase in triacylglycerol level, accompanied with increased number and size of lipid droplets in gcr1∆ cells. The expression of pT1, pT2 truncations in opi3∆ cells revealed the -1 to -500 bp in the promoter region is essential for the activation of OPI3 transcription. The mutation specifically at UASCT box (-265) in the OPI3 promoter region displayed a reduction in the PC level and the additional mutation at UASINO (-165) further reduced the PC level. Collectively, our data suggest that the GCR1 transcription factor also regulates the OPI3 expression and has an impact on lipid homeostasis.
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Affiliation(s)
- Ravi Chidambaram
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Gowsalya Ramachandran
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
| | - Ram Rajasekharan
- Department of Microbiology, Central University of Tamil Nadu, Tamil Nadu, India
| | - Vasanthi Nachiappan
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India
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Laborda P, Martínez JL, Hernando‐Amado S. Convergent phenotypic evolution towards fosfomycin collateral sensitivity of Pseudomonas aeruginosa antibiotic-resistant mutants. Microb Biotechnol 2022; 15:613-629. [PMID: 33960651 PMCID: PMC8867969 DOI: 10.1111/1751-7915.13817] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 12/19/2022] Open
Abstract
The rise of antibiotic resistance and the reduced amount of novel antibiotics support the need of developing novel strategies to fight infections, based on improving the use of the antibiotics we already have. Collateral sensitivity is an evolutionary trade-off associated with the acquisition of antibiotic resistance that can be exploited to tackle this relevant health problem. However, different works have shown that patterns of collateral sensitivity are not always conserved, thus precluding the exploitation of this evolutionary trade-off to fight infections. In this work, we identify a robust pattern of collateral sensitivity to fosfomycin in Pseudomonas aeruginosa antibiotic-resistant mutants, selected by antibiotics belonging to different structural families. We characterize the underlying mechanism of the collateral sensitivity observed, which is a reduced expression of the genes encoding the peptidoglycan-recycling pathway, which preserves the peptidoglycan synthesis in situations where its de novo synthesis is blocked, and a reduced expression of fosA, encoding a fosfomycin-inactivating enzyme. We propose that the identification of robust collateral sensitivity patterns, as well as the understanding of the molecular mechanisms behind these phenotypes, would provide valuable information to design evolution-based strategies to treat bacterial infections.
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Affiliation(s)
- Pablo Laborda
- Centro Nacional de BiotecnologíaCSICMadrid28049Spain
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