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Chávez-Hernández EC, Quiroz S, García-Ponce B, Álvarez-Buylla ER. The flowering transition pathways converge into a complex gene regulatory network that underlies the phase changes of the shoot apical meristem in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:852047. [PMID: 36017258 PMCID: PMC9396034 DOI: 10.3389/fpls.2022.852047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/04/2022] [Indexed: 05/08/2023]
Abstract
Post-embryonic plant development is characterized by a period of vegetative growth during which a combination of intrinsic and extrinsic signals triggers the transition to the reproductive phase. To understand how different flowering inducing and repressing signals are associated with phase transitions of the Shoot Apical Meristem (SAM), we incorporated available data into a dynamic gene regulatory network model for Arabidopsis thaliana. This Flowering Transition Gene Regulatory Network (FT-GRN) formally constitutes a dynamic system-level mechanism based on more than three decades of experimental data on flowering. We provide novel experimental data on the regulatory interactions of one of its twenty-three components: a MADS-box transcription factor XAANTAL2 (XAL2). These data complement the information regarding flowering transition under short days and provides an example of the type of questions that can be addressed by the FT-GRN. The resulting FT-GRN is highly connected and integrates developmental, hormonal, and environmental signals that affect developmental transitions at the SAM. The FT-GRN is a dynamic multi-stable Boolean system, with 223 possible initial states, yet it converges into only 32 attractors. The latter are coherent with the expression profiles of the FT-GRN components that have been experimentally described for the developmental stages of the SAM. Furthermore, the attractors are also highly robust to initial states and to simulated perturbations of the interaction functions. The model recovered the meristem phenotypes of previously described single mutants. We also analyzed the attractors landscape that emerges from the postulated FT-GRN, uncovering which set of signals or components are critical for reproductive competence and the time-order transitions observed in the SAM. Finally, in the context of such GRN, the role of XAL2 under short-day conditions could be understood. Therefore, this model constitutes a robust biological module and the first multi-stable, dynamical systems biology mechanism that integrates the genetic flowering pathways to explain SAM phase transitions.
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Affiliation(s)
- Elva C. Chávez-Hernández
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Stella Quiroz
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- *Correspondence: Berenice García-Ponce,
| | - Elena R. Álvarez-Buylla
- Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Elena R. Álvarez-Buylla,
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Davila-Velderrain J, Caldu-Primo JL, Martinez-Garcia JC, Alvarez-Buylla ER. Modeling the Epigenetic Landscape in Plant Development. Methods Mol Biol 2018; 1819:357-383. [PMID: 30421413 DOI: 10.1007/978-1-4939-8618-7_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Computational mechanistic models enable a systems-level understanding of plant development by integrating available molecular experimental data and simulating their collective dynamical behavior. Boolean gene regulatory network dynamical models have been extensively used as a qualitative modeling framework for such purpose. More recently, network modeling protocols have been extended to model the epigenetic landscape associated with gene regulatory networks. In addition to understanding the concerted action of interconnected genes, epigenetic landscape models aim to uncover the patterns of cell state transition events that emerge under diverse genetic and environmental background conditions. In this chapter we present simple protocols that naturally extend gene regulatory network modeling and demonstrate their use in modeling plant developmental processes under the epigenetic landscape framework. We focus on conceptual clarity and practical implementation, providing directions to the corresponding technical literature. The protocols presented here can be applied to any well-characterized gene regulatory network in plants, animals, or human disease.
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Affiliation(s)
- Jose Davila-Velderrain
- Centro de Ciencias de la Complejidad (C3), Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F, Mexico.,Departamento de Control Automático, Cinvestav-IPN, México D.F, Mexico.,MIT Computer Science and Artificial Intelligence Laboratory, Cambridge, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jose Luis Caldu-Primo
- Centro de Ciencias de la Complejidad (C3), Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F, Mexico
| | | | - Elena R Alvarez-Buylla
- Centro de Ciencias de la Complejidad (C3), Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F, Mexico. .,Laboratorio de Genética Molecular, Desarrollo y Evolución de Plantas, Instituto de Ecología, México D.F, Mexico. .,University of California, Berkeley, Berkley, CA, USA.
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Cajero Sánchez W, García-Ponce B, Sánchez MDLP, Álvarez-Buylla ER, Garay-Arroyo A. Identifying the transition to the maturation zone in three ecotypes of Arabidopsis thaliana roots. Commun Integr Biol 2017; 11:e1395993. [PMID: 29497470 PMCID: PMC5824961 DOI: 10.1080/19420889.2017.1395993] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/17/2017] [Accepted: 10/18/2017] [Indexed: 11/23/2022] Open
Abstract
The Arabidopsis thaliana (hereafter Arabidopsis) root has become a useful model for studying how organ morphogenesis emerge from the coordination and balance of cell proliferation and differentiation, as both processes may be observed and quantified in the root at different stages of development. Hence, being able to objectively identify and delimit the different stages of root development has been very important. Up to now, three different zones along the longitudinal axis of the primary root of Arabidopsis, have been identified: the root apical meristematic zone (RAM) with two domains [the proliferative (PD) and the transition domain (TD)], the elongation zone (EZ) and the maturation zone (MZ). We previously reported a method to quantify the length of the cells of the meristematic and the elongation zone, as well as the boundaries or transitions between the root domains along the growing part of the Arabidopsis root. In this study, we provide a more accurate criterion to identify the MZ. Traditionally, the transition between the EZ to the MZ has been established by the emergence of the first root-hair bulge in the epidermis, because this emergence coincides with cell maturation in this cell type. But we have found here that after the emergence of the first root-hair bulge some cells continue to elongate and we have confirmed this in three different Arabidopsis ecotypes. We established the limit between the EZ and the MZ by looking for the closest cortical cell with a longer length than the average cell length of 10 cells after the cortical cell closest to the epidermal cell with the first root-hair bulge in these three ecotypes. In Col-0 and Ws this cell is four cells above the one with the root hair bulge and, in the Ler ecotype, this cell is five cells above. To unambiguously identifying the site at which cells stop elongating and attain their final length and fate at the MZ, we propose to calculate the length of completely elongated cortical cells counting 10 cells starting from the sixth cell above the cortical cell closest to the epidermal cell with the first root-hair bulge. We validated this proposal in the three ecotypes analyzed and consider that this proposal may aid at having a more objective way to characterize root phenotypes and compare among them.
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Affiliation(s)
- Wendy Cajero Sánchez
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, Ciudad de México, Mexico
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, Ciudad de México, Mexico
| | - María de la Paz Sánchez
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, Ciudad de México, Mexico
| | - Elena R Álvarez-Buylla
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, Ciudad de México, Mexico
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Desarrollo, Evolución y Epigenética de Plantas, Universidad Nacional Autónoma de México, 3er Circuito Exterior junto al Jardín Botánico, Ciudad Universitaria, Ciudad de México, Mexico
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Méndez-López LF, Davila-Velderrain J, Domínguez-Hüttinger E, Enríquez-Olguín C, Martínez-García JC, Alvarez-Buylla ER. Gene regulatory network underlying the immortalization of epithelial cells. BMC SYSTEMS BIOLOGY 2017; 11:24. [PMID: 28209158 PMCID: PMC5314717 DOI: 10.1186/s12918-017-0393-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/11/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND Tumorigenic transformation of human epithelial cells in vitro has been described experimentally as the potential result of spontaneous immortalization. This process is characterized by a series of cell-state transitions, in which normal epithelial cells acquire first a senescent state which is later surpassed to attain a mesenchymal stem-like phenotype with a potentially tumorigenic behavior. In this paper we aim to provide a system-level mechanistic explanation to the emergence of these cell types, and to the time-ordered transition patterns that are common to neoplasias of epithelial origin. To this end, we first integrate published functional and well-curated molecular data of the components and interactions that have been found to be involved in such cell states and transitions into a network of 41 molecular components. We then reduce this initial network by removing simple mediators (i.e., linear pathways), and formalize the resulting regulatory core into logical rules that govern the dynamics of each of the network components as a function of the states of its regulators. RESULTS Computational dynamic analysis shows that our proposed Gene Regulatory Network model recovers exactly three attractors, each of them defined by a specific gene expression profile that corresponds to the epithelial, senescent, and mesenchymal stem-like cellular phenotypes, respectively. We show that although a mesenchymal stem-like state can be attained even under unperturbed physiological conditions, the likelihood of converging to this state is increased when pro-inflammatory conditions are simulated, providing a systems-level mechanistic explanation for the carcinogenic role of chronic inflammatory conditions observed in the clinic. We also found that the regulatory core yields an epigenetic landscape that restricts temporal patterns of progression between the steady states, such that recovered patterns resemble the time-ordered transitions observed during the spontaneous immortalization of epithelial cells, both in vivo and in vitro. CONCLUSION Our study strongly suggests that the in vitro tumorigenic transformation of epithelial cells, which strongly correlates with the patterns observed during the pathological progression of epithelial carcinogenesis in vivo, emerges from underlying regulatory networks involved in epithelial trans-differentiation during development.
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Affiliation(s)
- Luis Fernando Méndez-López
- Centro de Investigación y Desarrollo en Ciencias de la Salud (CIDICS), Universidad Autonoma de Nuevo Leon, A. P. 14-740, México, 07300 D.F México
| | | | - Elisa Domínguez-Hüttinger
- Instituto de Ecología, UNAM, Cd. Universitaria, México, 04510 D.F México
- Centro de Ciencias de la Complejidad, UNAM, Cd. Universitaria, México, 04510 D.F México
| | | | | | - Elena R. Alvarez-Buylla
- Instituto de Ecología, UNAM, Cd. Universitaria, México, 04510 D.F México
- Centro de Ciencias de la Complejidad, UNAM, Cd. Universitaria, México, 04510 D.F México
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de la Paz Sanchez M, Aceves-García P, Petrone E, Steckenborn S, Vega-León R, Álvarez-Buylla ER, Garay-Arroyo A, García-Ponce B. The impact of Polycomb group (PcG) and Trithorax group (TrxG) epigenetic factors in plant plasticity. THE NEW PHYTOLOGIST 2015; 208:684-694. [PMID: 26037337 DOI: 10.1111/nph.13486] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 04/25/2015] [Indexed: 06/04/2023]
Abstract
Current advances indicate that epigenetic mechanisms play important roles in the regulatory networks involved in plant developmental responses to environmental conditions. Hence, understanding the role of such components becomes crucial to understanding the mechanisms underlying the plasticity and variability of plant traits, and thus the ecology and evolution of plant development. We now know that important components of phenotypic variation may result from heritable and reversible epigenetic mechanisms without genetic alterations. The epigenetic factors Polycomb group (PcG) and Trithorax group (TrxG) are involved in developmental processes that respond to environmental signals, playing important roles in plant plasticity. In this review, we discuss current knowledge of TrxG and PcG functions in different developmental processes in response to internal and environmental cues and we also integrate the emerging evidence concerning their function in plant plasticity. Many such plastic responses rely on meristematic cell behavior, including stem cell niche maintenance, cellular reprogramming, flowering and dormancy as well as stress memory. This information will help to determine how to integrate the role of epigenetic regulation into models of gene regulatory networks, which have mostly included transcriptional interactions underlying various aspects of plant development and its plastic response to environmental conditions.
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Affiliation(s)
- Maria de la Paz Sanchez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Pamela Aceves-García
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Emilio Petrone
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Stefan Steckenborn
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Rosario Vega-León
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Elena R Álvarez-Buylla
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de plantas, Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM), 3er Circuito Ext Junto a J. Botánico, Ciudad Universitaria, México, DF 04510, Mexico
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