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Kenny-Ganzert IW, Sherwood DR. The C. elegans anchor cell: A model to elucidate mechanisms underlying invasion through basement membrane. Semin Cell Dev Biol 2024; 154:23-34. [PMID: 37422376 PMCID: PMC10592375 DOI: 10.1016/j.semcdb.2023.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 06/30/2023] [Accepted: 07/01/2023] [Indexed: 07/10/2023]
Abstract
Cell invasion through basement membrane barriers is crucial during many developmental processes and in immune surveillance. Dysregulation of invasion also drives the pathology of numerous human diseases, such as metastasis and inflammatory disorders. Cell invasion involves dynamic interactions between the invading cell, basement membrane, and neighboring tissues. Owing to this complexity, cell invasion is challenging to study in vivo, which has hampered the understanding of mechanisms controlling invasion. Caenorhabditis elegans anchor cell invasion is a powerful in vivo model where subcellular imaging of cell-basement membrane interactions can be combined with genetic, genomic, and single-cell molecular perturbation studies. In this review, we outline insights gained by studying anchor cell invasion, which span transcriptional networks, translational regulation, secretory apparatus expansion, dynamic and adaptable protrusions that breach and clear basement membrane, and a complex, localized metabolic network that fuels invasion. Together, investigation of anchor cell invasion is building a comprehensive understanding of the mechanisms that underlie invasion, which we expect will ultimately facilitate better therapeutic strategies to control cell invasive activity in human disease.
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Affiliation(s)
| | - David R Sherwood
- Department of Biology, Duke University, Box 90338, Durham, NC 27708, USA.
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2
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Laub V, Devraj K, Elias L, Schulte D. Bioinformatics for wet-lab scientists: practical application in sequencing analysis. BMC Genomics 2023; 24:382. [PMID: 37420172 DOI: 10.1186/s12864-023-09454-7] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/15/2023] [Indexed: 07/09/2023] Open
Abstract
BACKGROUND Genomics data is available to the scientific community after publication of research projects and can be investigated for a multitude of research questions. However, in many cases deposited data is only assessed and used for the initial publication, resulting in valuable resources not being exploited to their full depth. MAIN: A likely reason for this is that many wetlab-based researchers are not formally trained to apply bioinformatic tools and may therefore assume that they lack the necessary experience to do so themselves. In this article, we present a series of freely available, predominantly web-based platforms and bioinformatic tools that can be combined in analysis pipelines to interrogate different types of next-generation sequencing data. Additionally to the presented exemplary route, we also list a number of alternative tools that can be combined in a mix-and-match fashion. We place special emphasis on tools that can be followed and used correctly without extensive prior knowledge in programming. Such analysis pipelines can be applied to existing data downloaded from the public domain or be compared to the results of own experiments. CONCLUSION Integrating transcription factor binding to chromatin (ChIP-seq) with transcriptional output (RNA-seq) and chromatin accessibility (ATAC-seq) can not only assist to form a deeper understanding of the molecular interactions underlying transcriptional regulation but will also help establishing new hypotheses and pre-testing them in silico.
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Affiliation(s)
- Vera Laub
- Neurological Institute (Edinger Institute), University Hospital Frankfurt, Goethe University, Frankfurt, Germany.
| | - Kavi Devraj
- Neurological Institute (Edinger Institute), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
- Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, India
| | - Lena Elias
- Neurological Institute (Edinger Institute), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Dorothea Schulte
- Neurological Institute (Edinger Institute), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
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Wang L, Li J, Wang C, Tang R, Liang J, Gong Y, Dai Y, Ding N, Wu J, Dai N, Liu L, Zhao Y, Shao Y, Zhao W, Jiang P, Shi X, Chen W, Tian Y, Liu X, Ma X, Sun Z. Mapping of de novo mutations in primary biliary cholangitis to a disease-specific co-expression network underlying homeostasis and metabolism. J Genet Genomics 2021:S1673-8527(21)00265-4. [PMID: 34433101 DOI: 10.1016/j.jgg.2021.07.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023]
Abstract
Primary biliary cholangitis (PBC) is an autoimmune disease involving dysregulation of a broad array of homeostatic and metabolic processes. Although considerable single-nucleotide polymorphisms have been unveiled, a large fraction of risk factors remains enigmatic. Candidate genes with rare mutations that tend to confer more deleterious effects need to be identified. To help pinpoint cellular and developmental mechanisms beyond common noncoding variants, we integrated whole exome sequencing with integrative network analysis to investigate genes harboring de novo mutations. Prominent convergence has been revealed on a network of disease-specific co-expression comprised of 55 genes associated with homeostasis and metabolism. The transcription factor MEF2D and the DNA repair gene PARP2 were highlighted as hub genes and identified to be up- and down-regulated, respectively, in peripheral blood data set. Enrichment analysis demonstrated altered expression of MEF2D and PARP2 may trigger a series of molecular and cellular processes with pivotal roles in PBC pathophysiology. Our study identified genes with de novo mutations in PBC and suggested a subset of genes in homeostasis and metabolism tend to act in synergy through converging on co-expression network, providing novel insights into the etiology of PBC and expanding the pool of molecular candidates for discovering clinically actionable biomarkers.
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Yao B, Zhou Z, Zhang M, Leng X, Zhao D. Comparison of Gene Expression Patterns in Articular Cartilage and Xiphoid Cartilage. Biochem Genet 2021. [PMID: 34410558 DOI: 10.1007/s10528-021-10127-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 08/13/2021] [Indexed: 10/20/2022]
Abstract
Cartilage is a resilient and smooth connective tissue that is found throughout the body. Among the three major types of cartilage, namely hyaline cartilage, elastic cartilage, and fibrocartilage, hyaline cartilage is the most widespread type of cartilage predominantly located in the joint surfaces (articular cartilage, AC). It remains a huge challenge for orthopedic surgeons to deal with AC damage since it has limited capacity for self-repair. Xiphoid cartilage (XC) is a vestigial cartilage located in the distal end of the sternum. XC-derived chondrocytes exhibit strong chondrogenic differentiation capacity. Thus, XC could become a potential donor site of chondrocytes for cartilage repair and regeneration. However, the underlying gene expression patterns between AC and XC are still largely unknown. In the present study, we used state-of-the-art RNA-seq technology combined with validation method to investigate the gene expression patterns between AC and XC, and identified a series of differentially expressed genes (DEGs) involved in chondrocyte commitment and differentiation including growth factors, transcription factors, and extracellular matrices. We demonstrated that the majority of significantly up-regulated DEGs (XC vs. AC) in XC were involved in regulating cartilage regeneration and repair, whereas the majority of significantly up-regulated DEGs (XC vs. AC) in AC were involved in regulating chondrocyte differentiation and maturation. This study has increased our knowledge of transcriptional networks in hyaline cartilage and elastic cartilage. It also supports the use of XC-derived chondrocytes as a potential cell resource for cartilage regeneration and repair.
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Shohayeb B, Muzar Z, Cooper HM. Conservation of neural progenitor identity and the emergence of neocortical neuronal diversity. Semin Cell Dev Biol 2021; 118:4-13. [PMID: 34083116 DOI: 10.1016/j.semcdb.2021.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 11/27/2022]
Abstract
One paramount challenge for neuroscientists over the past century has been to identify the embryonic origins of the enormous diversity of cortical neurons found in the adult human neocortex and to unravel the developmental processes governing their emergence. In all mammals, including humans, the radial glia lining the ventricles of the embryonic telencephalon, more recently reclassified as apical radial glia (aRGs), have been identified as the neural progenitors giving rise to all excitatory neurons and inhibitory interneurons of the six-layered cortex. In this review, we explore the fundamental molecular and cellular mechanisms that regulate aRG function and the generation of neuronal diversity in the dorsal telencephalon. We survey the key structural features essential for the retention of the highly polarized aRG morphology and therefore impose aRG identity after cytokinesis. We discuss how these structures and associated molecular signaling complexes influence aRG proliferative capacity and the decision to undergo proliferative self-renewing symmetric or neurogenic asymmetric divisions. We also explore the intriguing and complex question of how the extensive neuronal diversity within the adult neocortex arises from the small aRG population located within the cortical proliferative zone. We further highlight the recent clonal lineage tracing and single-cell transcriptomic profiling studies providing compelling evidence that individual neuronal identity emerges as a consequence of exposure to temporally regulated extrinsic cues which coordinate waves of transcriptional activity that evolve over time to drive neuronal commitment and maturation.
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Affiliation(s)
- Belal Shohayeb
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland 4072, Australia.
| | - Zukhrofi Muzar
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland 4072, Australia
| | - Helen M Cooper
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland 4072, Australia.
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6
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Abstract
Diverse cellular phenotypes are determined by groups of transcription factors (TFs) and other regulators that influence each others' gene expression, forming transcriptional gene regulatory networks (GRNs). In many biological contexts, especially in development and associated diseases, the expression of the genes in GRNs is not static but evolves in time. Modeling the dynamics of GRN state is an important approach for understanding diverse cellular phenomena such as cell-fate specification, pluripotency and cell-fate reprogramming, oncogenesis, and tissue regeneration. In this protocol, we describe how to model GRNs using a data-driven dynamic modeling methodology, gene circuits. Gene circuits do not require knowledge of the GRN topology and connectivity but instead learn them from training data, making them very general and applicable to diverse biological contexts. We utilize the MATLAB-based gene circuit modeling software Fast Inference of Gene Regulation (FIGR) for training the model on quantitative gene expression data and simulating the GRN. We describe all the steps in the modeling life cycle, from formulating the model, training the model using FIGR, simulating the GRN, to analyzing and interpreting the model output. This protocol highlights these steps with the example of a dynamical model of the gap gene GRN involved in Drosophila segmentation and includes example MATLAB statements for each step.
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Affiliation(s)
- Joanna E Handzlik
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Yen Lee Loh
- Department of Physics and Astrophysics, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Manu
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA.
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Trivedi A, Mehrotra A, Baum CE, Lewis B, Basuroy T, Blomquist T, Trumbly R, Filipp FV, Setaluri V, de la Serna IL. Bromodomain and extra-terminal domain (BET) proteins regulate melanocyte differentiation. Epigenetics Chromatin 2020; 13:14. [PMID: 32151278 PMCID: PMC7063807 DOI: 10.1186/s13072-020-00333-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [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: 08/21/2019] [Accepted: 02/19/2020] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Pharmacologic inhibition of bromodomain and extra-terminal (BET) proteins is currently being explored as a new therapeutic approach in cancer. Some studies have also implicated BET proteins as regulators of cell identity and differentiation through their interactions with lineage-specific factors. However, the role of BET proteins has not yet been investigated in melanocyte differentiation. Melanocyte inducing transcription factor (MITF) is the master regulator of melanocyte differentiation, essential for pigmentation and melanocyte survival. In this study, we tested the hypothesis that BET proteins regulate melanocyte differentiation through interactions with MITF. RESULTS Here we show that chemical inhibition of BET proteins prevents differentiation of unpigmented melanoblasts into pigmented melanocytes and results in de-pigmentation of differentiated melanocytes. BET inhibition also slowed cell growth, without causing cell death, increasing the number of cells in G1. Transcriptional profiling revealed that BET inhibition resulted in decreased expression of pigment-specific genes, including many MITF targets. The expression of pigment-specific genes was also down-regulated in melanoma cells, but to a lesser extent. We found that RNAi depletion of the BET family members, bromodomain-containing protein 4 (BRD4) and bromodomain-containing protein 2 (BRD2) inhibited expression of two melanin synthesis enzymes, TYR and TYRP1. Both BRD4 and BRD2 were detected on melanocyte promoters surrounding MITF-binding sites, were associated with open chromatin structure, and promoted MITF binding to these sites. Furthermore, BRD4 and BRD2 physically interacted with MITF. CONCLUSION These findings indicate a requirement for BET proteins in the regulation of pigmentation and melanocyte differentiation. We identified changes in pigmentation specific gene expression that occur upon BET inhibition in melanoblasts, melanocytes, and melanoma cells.
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Affiliation(s)
- Archit Trivedi
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
| | - Aanchal Mehrotra
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
- Present Address: Department of Genome Sciences, University of Washington School of Medicine, 1959 NE Pacific St, Seattle, WA 98195 USA
| | - Caitlin E. Baum
- Department of Pathology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
| | - Brandon Lewis
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
| | - Tupa Basuroy
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
- Present Address: Cancer Center Division, Massachusetts General Hospital Harvard Medical School, 149 Thirteenth Street, 7th Floor, Charlestown, MA 02129 USA
| | - Thomas Blomquist
- Department of Pathology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
| | - Robert Trumbly
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
| | - Fabian V. Filipp
- Cancer Systems Biology, Institute of Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, München, 85764 Germany
- School of Life Sciences Weihenstephan, Technical University München, Maximus-von-Imhof-Forum 3, Freising, 85354 Germany
| | - Vijayasaradhi Setaluri
- Department of Dermatology, University of Wisconsin-Madison, The School of Medicine and Public Health, 1 S. Park Street, Madison, WI 53715 USA
| | - Ivana L. de la Serna
- Department of Cancer Biology, University of Toledo College of Medicine and Life Sciences, 3035 Arlington Ave, Toledo, OH 43614 USA
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Hui Y, Wei PJ, Xia J, Wang YT, Zheng CH. MECoRank: cancer driver genes discovery simultaneously evaluating the impact of SNVs and differential expression on transcriptional networks. BMC Med Genomics 2019; 12:140. [PMID: 31888623 PMCID: PMC6936061 DOI: 10.1186/s12920-019-0582-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 09/10/2019] [Indexed: 01/09/2023] Open
Abstract
Background Although there are huge volumes of genomic data, how to decipher them and identify driver events is still a challenge. The current methods based on network typically use the relationship between genomic events and consequent changes in gene expression to nominate putative driver genes. But there may exist some relationships within the transcriptional network. Methods We developed MECoRank, a novel method that improves the recognition accuracy of driver genes. MECoRank is based on bipartite graph to propagates the scores via an iterative process. After iteration, we will obtain a ranked gene list for each patient sample. Then, we applied the Condorcet voting method to determine the most impactful drivers in a population. Results We applied MECoRank to three cancer datasets to reveal candidate driver genes which have a greater impact on gene expression. Experimental results show that our method not only can identify more driver genes that have been validated than other methods, but also can recognize some impactful novel genes which have been proved to be more important in literature. Conclusions We propose a novel approach named MECoRank to prioritize driver genes based on their impact on the expression in the molecular interaction network. This method not only assesses mutation’s effect on the transcriptional network, but also assesses the differential expression’s effect within the transcriptional network. And the results demonstrated that MECoRank has better performance than the other competing approaches in identifying driver genes.
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Affiliation(s)
- Ying Hui
- Key Lab of Intelligent Computing and Signal Processing of Ministry of Education, College of Computer Science and Technology, Anhui University, Hefei, China
| | - Pi-Jing Wei
- Key Lab of Intelligent Computing and Signal Processing of Ministry of Education, College of Computer Science and Technology, Anhui University, Hefei, China
| | - Junfeng Xia
- Institute of Physical Science and Information Technology, Anhui University, Hefei, China
| | - Yu-Tian Wang
- School of Software Engineering, Qufu Normal University, Qufu, China
| | - Chun-Hou Zheng
- Key Lab of Intelligent Computing and Signal Processing of Ministry of Education, College of Computer Science and Technology, Anhui University, Hefei, China.
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Grinevich DO, Desai JS, Stroup KP, Duan J, Slabaugh E, Doherty CJ. Novel transcriptional responses to heat revealed by turning up the heat at night. Plant Mol Biol 2019; 101:1-19. [PMID: 31062216 PMCID: PMC6695350 DOI: 10.1007/s11103-019-00873-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 04/11/2019] [Indexed: 05/29/2023]
Abstract
KEY MESSAGE The circadian clock controls many molecular activities, impacting experimental interpretation. We quantify the genome-wide effects of time-of-day on the heat-shock response and the effects of "diurnal bias" in stress experiments. Heat stress has significant adverse effects on plant productivity worldwide. Most experiments examining heat stress are performed during daytime hours, generating a 'diurnal bias' in the pathways and regulatory mechanisms identified. Such bias may confound downstream interpretations and limit our understanding of the full response to heat stress. Here we show that the transcriptional and physiological responses to a sudden heat shock in Arabidopsis are profoundly sensitive to the time of day. We observe that plant tolerance and acclimation to heat shock vary throughout the day and are maximal at dusk. Consistently, over 75% of heat-responsive transcripts show a time of day-dependent response, including many previously characterized heat-response genes. This temporal sensitivity implies a complex interaction between time and temperature where daily variations in basal transcription influence thermotolerance. When we examined these transcriptional responses, we uncovered novel night-response genes and cis-regulatory elements, underpinning new aspects of heat stress responses not previously appreciated. Exploiting this temporal variation can be applied to most environmental responses to understand the underlying network wiring. Therefore, we propose that using time as a perturbagen is an approach that will enhance our understanding of plant regulatory networks and responses to environmental stresses.
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Affiliation(s)
- Dmitry O. Grinevich
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Jigar S. Desai
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Kevin P. Stroup
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Jiaqi Duan
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Erin Slabaugh
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
| | - Colleen J. Doherty
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, USA
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Izadi F. Differential Connectivity in Colorectal Cancer Gene Expression Network. Iran Biomed J 2019; 23. [PMID: 29843204 PMCID: PMC6305824 DOI: 10.29252/.23.1.34] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Colorectal cancer (CRC) is one of the challenging types of cancers; thus, exploring effective biomarkers related to colorectal could lead to significant progresses toward the treatment of this disease. METHODS In the present study, CRC gene expression datasets have been reanalyzed. Mutual differentially expressed genes across 294 normal mucosa and adjacent tumoral samples were then utilized in order to build two independent transcriptional regulatory networks. By analyzing the networks topologically, genes with differential global connectivity related to cancer state were determined for which the potential transcriptional regulators including transcription factors were identified. RESULTS The majority of differentially connected genes (DCGs) were up-regulated in colorectal transcriptome experiments. Moreover, a number of these genes have been experimentally validated as cancer or CRC-associated genes. The DCGs, including GART, TGFB1, ITGA2, SLC16A5, SOX9, and MMP7, were investigated across 12 cancer types. Functional enrichment analysis followed by detailed data mining exhibited that these candidate genes could be related to CRC by mediating in metastatic cascade in addition to shared pathways with 12 cancer types by triggering the inflammatory events. DISCUSSION Our study uncovered correlated alterations in gene expression related to CRC susceptibility and progression that the potent candidate biomarkers could provide a link to disease.
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Affiliation(s)
- Fereshteh Izadi
- Sari Agricultural Sciences and Natural Resources University (SANRU), Farah Abad Road, Mazandaran 4818168984, Iran,Corresponding Author: Fereshteh Izadi Sari Agricultural Sciences and Natural Resources University (SANRU), Farah Abad Road, Mazandaran 4818168984, Iran; Mobile: (+98-918) 6291302; E-mail:
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11
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Abstract
Multicellular organisms, such as plants, fungi, and animals, develop organs with specialized functions. Major challenges in developing such structures include establishment of polarity along three axes (apical-basal, medio-lateral, and dorso-ventral/abaxial-adaxial), specification of tissue types and their coordinated growth, and maintenance of communication between the organ and the entire organism. The gynoecium of the model plant Arabidopsis thaliana embodies the female reproductive organ and has proven an excellent model system for studying organ establishment and development, given its division into different regions with distinct symmetries and highly diverse tissue types. Upon pollination, the gynoecium undergoes dramatic changes in morphology and developmental programming to form the seed-containing fruit. In this review, we wish to provide a detailed overview of the molecular and genetic mechanisms that are known to guide gynoecium and fruit development in A. thaliana. We describe networks of key genetic regulators and their interactions with hormonal dynamics in driving these developmental processes. The discoveries made to date clearly demonstrate that conclusions drawn from studying gynoecium and fruit development in flowering plants can be used to further our general understanding of organ formation across the plant kingdom. Importantly, this acquired knowledge is increasingly being used to improve fruit and seed crops, facilitated by the recent profound advances in genomics, cloning, and gene-editing technologies.
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Affiliation(s)
- Sara Simonini
- Department of Crop Genetics, John Innes Centre, Norwich, United Kingdom
| | - Lars Østergaard
- Department of Crop Genetics, John Innes Centre, Norwich, United Kingdom.
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Jambusaria A, Klomp J, Hong Z, Rafii S, Dai Y, Malik AB, Rehman J. A computational approach to identify cellular heterogeneity and tissue-specific gene regulatory networks. BMC Bioinformatics 2018; 19:217. [PMID: 29940845 PMCID: PMC6019795 DOI: 10.1186/s12859-018-2190-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 05/04/2018] [Indexed: 01/26/2023] Open
Abstract
Background The heterogeneity of cells across tissue types represents a major challenge for studying biological mechanisms as well as for therapeutic targeting of distinct tissues. Computational prediction of tissue-specific gene regulatory networks may provide important insights into the mechanisms underlying the cellular heterogeneity of cells in distinct organs and tissues. Results Using three pathway analysis techniques, gene set enrichment analysis (GSEA), parametric analysis of gene set enrichment (PGSEA), alongside our novel model (HeteroPath), which assesses heterogeneously upregulated and downregulated genes within the context of pathways, we generated distinct tissue-specific gene regulatory networks. We analyzed gene expression data derived from freshly isolated heart, brain, and lung endothelial cells and populations of neurons in the hippocampus, cingulate cortex, and amygdala. In both datasets, we found that HeteroPath segregated the distinct cellular populations by identifying regulatory pathways that were not identified by GSEA or PGSEA. Using simulated datasets, HeteroPath demonstrated robustness that was comparable to what was seen using existing gene set enrichment methods. Furthermore, we generated tissue-specific gene regulatory networks involved in vascular heterogeneity and neuronal heterogeneity by performing motif enrichment of the heterogeneous genes identified by HeteroPath and linking the enriched motifs to regulatory transcription factors in the ENCODE database. Conclusions HeteroPath assesses contextual bidirectional gene expression within pathways and thus allows for transcriptomic assessment of cellular heterogeneity. Unraveling tissue-specific heterogeneity of gene expression can lead to a better understanding of the molecular underpinnings of tissue-specific phenotypes. Electronic supplementary material The online version of this article (10.1186/s12859-018-2190-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ankit Jambusaria
- Department of Pharmacology, The University of Illinois College of Medicine, 835 S. Wolcott Ave. Rm. E403, Chicago, IL, 60612, USA.,Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, USA
| | - Jeff Klomp
- Department of Pharmacology, The University of Illinois College of Medicine, 835 S. Wolcott Ave. Rm. E403, Chicago, IL, 60612, USA
| | - Zhigang Hong
- Department of Pharmacology, The University of Illinois College of Medicine, 835 S. Wolcott Ave. Rm. E403, Chicago, IL, 60612, USA
| | - Shahin Rafii
- Division of Regenerative Medicine, Department of Medicine, Ansary Stem Cell Institute, Weill Cornell Medicine, New York, NY, USA
| | - Yang Dai
- Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, USA
| | - Asrar B Malik
- Department of Pharmacology, The University of Illinois College of Medicine, 835 S. Wolcott Ave. Rm. E403, Chicago, IL, 60612, USA.
| | - Jalees Rehman
- Department of Pharmacology, The University of Illinois College of Medicine, 835 S. Wolcott Ave. Rm. E403, Chicago, IL, 60612, USA. .,Department of Bioengineering, The University of Illinois at Chicago, Chicago, IL, USA. .,Division of Cardiology, Department of Medicine, The University of Illinois College of Medicine, Chicago, IL, USA.
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13
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Gillen AE, Yang R, Cotton CU, Perez A, Randell SH, Leir SH, Harris A. Molecular characterization of gene regulatory networks in primary human tracheal and bronchial epithelial cells. J Cyst Fibros 2018; 17:444-453. [PMID: 29459038 DOI: 10.1016/j.jcf.2018.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 01/26/2018] [Accepted: 01/27/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Robust methods to culture primary airway epithelial cells were developed several decades ago and these cells provide the model of choice to investigate many diseases of the human lung. However, the molecular signature of cells from different regions of the airway epithelium has not been well characterized. METHODS We utilize DNase-seq and RNA-seq to examine the molecular signatures of primary cells derived from human tracheal and bronchial tissues, as well as healthy and diseased (cystic fibrosis (CF)) donor lung tissue. RESULTS Our data reveal an airway cell signature that is divergent from other epithelial cell types and from common airway epithelial cell lines. The differences between tracheal and bronchial cells are clearly evident as are common regulatory features. Only minor variation is seen between bronchial cells from healthy or CF donors. CONCLUSIONS These data are a valuable resource for functional genomics analysis of airway epithelial tissues in human disease.
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Affiliation(s)
- Austin E Gillen
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, 60614, United States; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, United States
| | - Rui Yang
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, 60614, United States; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, United States
| | - Calvin U Cotton
- Departments of Pediatrics, Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Aura Perez
- Departments of Pediatrics, Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Scott H Randell
- Marsico Lung Institute, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, United States
| | - Shih-Hsing Leir
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, 60614, United States; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, United States; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Ann Harris
- Human Molecular Genetics Program, Lurie Children's Research Center, Chicago, IL, 60614, United States; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, United States; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, United States.
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14
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Hintze M, Prajapati RS, Tambalo M, Christophorou NAD, Anwar M, Grocott T, Streit A. Cell interactions, signals and transcriptional hierarchy governing placode progenitor induction. Development 2017; 144:2810-2823. [PMID: 28684624 PMCID: PMC5560042 DOI: 10.1242/dev.147942] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [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: 12/19/2016] [Accepted: 06/21/2017] [Indexed: 12/18/2022]
Abstract
In vertebrates, cranial placodes contribute to all sense organs and sensory ganglia and arise from a common pool of Six1/Eya2+ progenitors. Here we dissect the events that specify ectodermal cells as placode progenitors using newly identified genes upstream of the Six/Eya complex. We show in chick that two different tissues, namely the lateral head mesoderm and the prechordal mesendoderm, gradually induce placode progenitors: cells pass through successive transcriptional states, each identified by distinct factors and controlled by different signals. Both tissues initiate a common transcriptional state but over time impart regional character, with the acquisition of anterior identity dependent on Shh signalling. Using a network inference approach we predict the regulatory relationships among newly identified transcription factors and verify predicted links in knockdown experiments. Based on this analysis we propose a new model for placode progenitor induction, in which the initial induction of a generic transcriptional state precedes regional divergence.
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Affiliation(s)
- Mark Hintze
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Ravindra Singh Prajapati
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Monica Tambalo
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Nicolas A D Christophorou
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Maryam Anwar
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Timothy Grocott
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Andrea Streit
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
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15
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Churchill AJ, Gutiérrez GD, Singer RA, Lorberbaum DS, Fischer KA, Sussel L. Genetic evidence that Nkx2.2 acts primarily downstream of Neurog3 in pancreatic endocrine lineage development. eLife 2017; 6. [PMID: 28071588 PMCID: PMC5224921 DOI: 10.7554/elife.20010] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 12/21/2016] [Indexed: 02/06/2023] Open
Abstract
Many pancreatic transcription factors that are essential for islet cell differentiation have been well characterized; however, because they are often expressed in several different cell populations, their functional hierarchy remains unclear. To parse out the spatiotemporal regulation of islet cell differentiation, we used a Neurog3-Cre allele to ablate Nkx2.2, one of the earliest and most broadly expressed islet transcription factors, specifically in the Neurog3+ endocrine progenitor lineage (Nkx2.2△endo). Remarkably, many essential components of the β cell transcriptional network that were down-regulated in the Nkx2.2KO mice, were maintained in the Nkx2.2△endo mice - yet the Nkx2.2△endo mice displayed defective β cell differentiation and recapitulated the Nkx2.2KO phenotype. This suggests that Nkx2.2 is not only required in the early pancreatic progenitors, but has additional essential activities within the endocrine progenitor population. Consistently, we demonstrate Nkx2.2 functions as an integral component of a modular regulatory program to correctly specify pancreatic islet cell fates. DOI:http://dx.doi.org/10.7554/eLife.20010.001
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Affiliation(s)
- Angela J Churchill
- Naomi Berrie Diabetes Institute, Columbia University Medical School, New York, Columbia.,Department of Genetics and Development, Columbia University Medical School, New York, Columbia.,Genetics and Development Doctoral Program, Columbia University Medical School, New York, Columbia
| | - Giselle Dominguez Gutiérrez
- Naomi Berrie Diabetes Institute, Columbia University Medical School, New York, Columbia.,Department of Genetics and Development, Columbia University Medical School, New York, Columbia.,Nutritional and Metabolic Biology Doctoral Program, Columbia University Medical School, New York, Columbia
| | - Ruth A Singer
- Naomi Berrie Diabetes Institute, Columbia University Medical School, New York, Columbia.,Department of Genetics and Development, Columbia University Medical School, New York, Columbia.,The Integrated Graduate Program in Cellular, Molecular and Biomedical Studies, Columbia University Medical School, New York, Columbia
| | | | - Kevin A Fischer
- Barbara Davis Center, University of Colorado, Denver, United States
| | - Lori Sussel
- Naomi Berrie Diabetes Institute, Columbia University Medical School, New York, Columbia.,Department of Genetics and Development, Columbia University Medical School, New York, Columbia.,Genetics and Development Doctoral Program, Columbia University Medical School, New York, Columbia.,Nutritional and Metabolic Biology Doctoral Program, Columbia University Medical School, New York, Columbia.,The Integrated Graduate Program in Cellular, Molecular and Biomedical Studies, Columbia University Medical School, New York, Columbia.,Barbara Davis Center, University of Colorado, Denver, United States
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16
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Abstract
RUNX transcription factors belong to a highly conserved class of transcriptional regulators which play various roles in the development of the majority of metazoans. In this review we focus on the founding member of the family, RUNX1, and its role in the transcriptional control of blood cell development in mammals. We summarize data showing that RUNX1 functions both as activator and repressor within a chromatin environment, a feature that requires its interaction with multiple other transcription factors and co-factors. Furthermore, we outline how RUNX1 works together with other factors to reshape the epigenetic landscape and the three-dimensional structure of gene loci within the nucleus. Finally, we review how aberrant forms of RUNX1 deregulate blood cell development and cause hematopoietic malignancies.
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Affiliation(s)
- Constanze Bonifer
- Institute for Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK.
| | - Elena Levantini
- Beth Israel Diaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Istituto di Tecnologie Biomediche, Consiglio Nazionale delle Richerche, Pisa, Italy
| | - Valerie Kouskoff
- Division of Developmental Biology & Medicine, The University of Manchester, Manchester, UK
| | - Georges Lacaud
- Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
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17
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Muñoz A, Santos Muñoz D, Zimin A, Yorke JA. Evolution of transcriptional networks in yeast: alternative teams of transcriptional factors for different species. BMC Genomics 2016; 17:826. [PMID: 28185554 PMCID: PMC5123246 DOI: 10.1186/s12864-016-3102-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Background The diversity in eukaryotic life reflects a diversity in regulatory pathways. Nocedal and Johnson argue that the rewiring of gene regulatory networks is a major force for the diversity of life, that changes in regulation can create new species. Results We have created a method (based on our new “ping-pong algorithm) for detecting more complicated rewirings, where several transcription factors can substitute for one or more transcription factors in the regulation of a family of co-regulated genes. An example is illustrative. A rewiring has been reported by Hogues et al. that RAP1 in Saccharomyces cerevisiae substitutes for TBF1/CBF1 in Candida albicans for ribosomal RP genes. There one transcription factor substitutes for another on some collection of genes. Such a substitution is referred to as a “rewiring”. We agree with this finding of rewiring as far as it goes but the situation is more complicated. Many transcription factors can regulate a gene and our algorithm finds that in this example a “team” (or collection) of three transcription factors including RAP1 substitutes for TBF1 for 19 genes. The switch occurs for a branch of the phylogenetic tree containing 10 species (including Saccharomyces cerevisiae), while the remaining 13 species (Candida albicans) are regulated by TBF1. Conclusions To gain insight into more general evolutionary mechanisms, we have created a mathematical algorithm that finds such general switching events and we prove that it converges. Of course any such computational discovery should be validated in the biological tests. For each branch of the phylogenetic tree and each gene module, our algorithm finds a sub-group of co-regulated genes and a team of transcription factors that substitutes for another team of transcription factors. In most cases the signal will be small but in some cases we find a strong signal of switching. We report our findings for 23 Ascomycota fungi species. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3102-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adriana Muñoz
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, 20742, USA. .,Department of Mathematics, University of Maryland, College Park, Maryland, 20742, USA. .,Cold Spring Harbor Laboratory, 1 Bungtown Rd., Cold Spring Harbor, 11724, NY, USA.
| | - Daniella Santos Muñoz
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, 20742, USA.,Department of Mathematics, University of Maryland, College Park, Maryland, 20742, USA.,Faculty of Sciences, University of Ottawa, Ottawa, K1N 6N5, ON, Canada.,Faculty of Engineering, University of Ottawa, Ottawa, K1N 6N5, ON, Canada
| | - Aleksey Zimin
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, 20742, USA
| | - James A Yorke
- Institute for Physical Science and Technology, University of Maryland, College Park, Maryland, 20742, USA.,Department of Mathematics, University of Maryland, College Park, Maryland, 20742, USA.,Department of Physics, University of Maryland, College Park, Maryland, 20742, USA
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18
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Anguita E, Gupta R, Olariu V, Valk PJ, Peterson C, Delwel R, Enver T. A somatic mutation of GFI1B identified in leukemia alters cell fate via a SPI1 (PU.1) centered genetic regulatory network. Dev Biol 2016; 411:277-286. [PMID: 26851695 DOI: 10.1016/j.ydbio.2016.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 01/22/2023]
Abstract
We identify a mutation (D262N) in the erythroid-affiliated transcriptional repressor GFI1B, in an acute myeloid leukemia (AML) patient with antecedent myelodysplastic syndrome (MDS). The GFI1B-D262N mutant functionally antagonizes the transcriptional activity of wild-type GFI1B. GFI1B-D262N promoted myelomonocytic versus erythroid output from primary human hematopoietic precursors and enhanced cell survival of both normal and MDS derived precursors. Re-analysis of AML transcriptome data identifies a distinct group of patients in whom expression of wild-type GFI1B and SPI1 (PU.1) have an inverse pattern. In delineating this GFI1B-SPI1 relationship we show that (i) SPI1 is a direct target of GFI1B, (ii) expression of GFI1B-D262N produces elevated expression of SPI1, and (iii) SPI1-knockdown restores balanced lineage output from GFI1B-D262N-expressing precursors. These results table the SPI1-GFI1B transcriptional network as an important regulatory axis in AML as well as in the development of erythroid versus myelomonocytic cell fate.
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Affiliation(s)
- Eduardo Anguita
- Hematology Department, Hospital Clínico San Carlos (IdISSC), Prof. Martín Lagos s/n, 28040 Madrid, Spain.
| | - Rajeev Gupta
- UCL Cancer Institute, Paul O'Gorman Building 72 Huntley St., London WC1E6BT, United Kingdom.
| | - Victor Olariu
- Computational Biology and Biological Physics Division, Lund University, Lund, Sweden.
| | - Peter J Valk
- Department of Hematology Erasmus University Medical Center, Rotterdam, Netherlands.
| | - Carsten Peterson
- Computational Biology and Biological Physics Division, Lund University, Lund, Sweden.
| | - Ruud Delwel
- Department of Hematology Erasmus University Medical Center, Rotterdam, Netherlands.
| | - Tariq Enver
- UCL Cancer Institute, Paul O'Gorman Building 72 Huntley St., London WC1E6BT, United Kingdom.
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19
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Garside VC, Cullum R, Alder O, Lu DY, Vander Werff R, Bilenky M, Zhao Y, Jones SJM, Marra MA, Underhill TM, Hoodless PA. SOX9 modulates the expression of key transcription factors required for heart valve development. Development 2015; 142:4340-50. [PMID: 26525672 DOI: 10.1242/dev.125252] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 10/28/2015] [Indexed: 01/10/2023]
Abstract
Heart valve formation initiates when endothelial cells of the heart transform into mesenchyme and populate the cardiac cushions. The transcription factor SOX9 is highly expressed in the cardiac cushion mesenchyme, and is essential for heart valve development. Loss of Sox9 in mouse cardiac cushion mesenchyme alters cell proliferation, embryonic survival, and valve formation. Despite this important role, little is known about how SOX9 regulates heart valve formation or its transcriptional targets. Therefore, we mapped putative SOX9 binding sites by ChIP-Seq in E12.5 heart valves, a stage at which the valve mesenchyme is actively proliferating and initiating differentiation. Embryonic heart valves have been shown to express a high number of genes that are associated with chondrogenesis, including several extracellular matrix proteins and transcription factors that regulate chondrogenesis. Therefore, we compared regions of putative SOX9 DNA binding between E12.5 heart valves and E12.5 limb buds. We identified context-dependent and context-independent SOX9-interacting regions throughout the genome. Analysis of context-independent SOX9 binding suggests an extensive role for SOX9 across tissues in regulating proliferation-associated genes including key components of the AP-1 complex. Integrative analysis of tissue-specific SOX9-interacting regions and gene expression profiles on Sox9-deficient heart valves demonstrated that SOX9 controls the expression of several transcription factors with previously identified roles in heart valve development, including Twist1, Sox4, Mecom and Pitx2. Together, our data identify SOX9-coordinated transcriptional hierarchies that control cell proliferation and differentiation during valve formation.
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Affiliation(s)
- Victoria C Garside
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Rebecca Cullum
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Olivia Alder
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Daphne Y Lu
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Ryan Vander Werff
- Biomedical Research Centre, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Mikhail Bilenky
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Yongjun Zhao
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada V5A 1S6
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - T Michael Underhill
- Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4 Biomedical Research Centre, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
| | - Pamela A Hoodless
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada V5Z 1L3 Program in Cell and Developmental Biology, University of British Columbia, Vancouver, Canada V6T 1Z4 Department of Medical Genetics, University of British Columbia, Vancouver, Canada V6T 1Z4
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20
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Cohen M, Page KM, Perez-Carrasco R, Barnes CP, Briscoe J. A theoretical framework for the regulation of Shh morphogen-controlled gene expression. Development 2014; 141:3868-78. [PMID: 25294939 PMCID: PMC4197706 DOI: 10.1242/dev.112573] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
How morphogen gradients govern the pattern of gene expression in developing tissues is not well understood. Here, we describe a statistical thermodynamic model of gene regulation that combines the activity of a morphogen with the transcriptional network it controls. Using Sonic hedgehog (Shh) patterning of the ventral neural tube as an example, we show that the framework can be used together with the principled parameter selection technique of approximate Bayesian computation to obtain a dynamical model that accurately predicts tissue patterning. The analysis indicates that, for each target gene regulated by Gli, which is the transcriptional effector of Shh signalling, there is a neutral point in the gradient, either side of which altering the Gli binding affinity has opposite effects on gene expression. This explains recent counterintuitive experimental observations. The approach is broadly applicable and provides a unifying framework to explain the temporospatial pattern of morphogen-regulated gene expression.
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Affiliation(s)
- Michael Cohen
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Karen M Page
- Department of Mathematics and CoMPLEX, University College London, Gower Street, London WC1E 6BT, UK
| | - Ruben Perez-Carrasco
- Department of Mathematics and CoMPLEX, University College London, Gower Street, London WC1E 6BT, UK
| | - Chris P Barnes
- Department of Cell and Developmental Biology and Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - James Briscoe
- MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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21
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Ciglar L, Girardot C, Wilczyński B, Braun M, Furlong EEM. Coordinated repression and activation of two transcriptional programs stabilizes cell fate during myogenesis. Development 2014; 141:2633-43. [PMID: 24961800 PMCID: PMC4146391 DOI: 10.1242/dev.101956] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Molecular models of cell fate specification typically focus on the activation of specific lineage programs. However, the concurrent repression of unwanted transcriptional networks is also essential to stabilize certain cellular identities, as shown in a number of diverse systems and phyla. Here, we demonstrate that this dual requirement also holds true in the context of Drosophila myogenesis. By integrating genetics and genomics, we identified a new role for the pleiotropic transcriptional repressor Tramtrack69 in myoblast specification. Drosophila muscles are formed through the fusion of two discrete cell types: founder cells (FCs) and fusion-competent myoblasts (FCMs). When tramtrack69 is removed, FCMs appear to adopt an alternative muscle FC-like fate. Conversely, ectopic expression of this repressor phenocopies muscle defects seen in loss-of-function lame duck mutants, a transcription factor specific to FCMs. This occurs through Tramtrack69-mediated repression in FCMs, whereas Lame duck activates a largely distinct transcriptional program in the same cells. Lineage-specific factors are therefore not sufficient to maintain FCM identity. Instead, their identity appears more plastic, requiring the combination of instructive repressive and activating programs to stabilize cell fate.
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Affiliation(s)
- Lucia Ciglar
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Charles Girardot
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Bartek Wilczyński
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Martina Braun
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117, Germany
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22
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Abstract
The Peroxisome Proliferator Activated Receptor alpha (PPARα) is a transcription factor that plays a major role in metabolic regulation. This review addresses the functional role of PPARα in intermediary metabolism and provides a detailed overview of metabolic genes targeted by PPARα, with a focus on liver. A distinction is made between the impact of PPARα on metabolism upon physiological, pharmacological, and nutritional activation. Low and high throughput gene expression analyses have allowed the creation of a comprehensive map illustrating the role of PPARα as master regulator of lipid metabolism via regulation of numerous genes. The map puts PPARα at the center of a regulatory hub impacting fatty acid uptake, fatty acid activation, intracellular fatty acid binding, mitochondrial and peroxisomal fatty acid oxidation, ketogenesis, triglyceride turnover, lipid droplet biology, gluconeogenesis, and bile synthesis/secretion. In addition, PPARα governs the expression of several secreted proteins that exert local and endocrine functions.
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23
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Gottschalk RA, Martins AJ, Sjoelund V, Angermann BR, Lin B, Germain RN. Recent progress using systems biology approaches to better understand molecular mechanisms of immunity. Semin Immunol 2012; 25:201-8. [PMID: 23238271 DOI: 10.1016/j.smim.2012.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/08/2012] [Indexed: 01/06/2023]
Abstract
The immune system is composed of multiple dynamic molecular and cellular networks, the complexity of which has been revealed by decades of exacting reductionist research. However, understanding of the immune system sufficient to anticipate its response to novel perturbations requires a more integrative or systems approach to immunology. While methods for unbiased high-throughput data acquisition and computational integration of the resulting datasets are still relatively new, they have begun to substantially enhance our understanding of immunological phenomena. Such approaches have expanded our view of interconnected signaling and transcriptional networks and have highlighted the function of non-linear processes such as spatial regulation and feedback loops. In addition, advances in single cell measurement technology have demonstrated potential sources and functions of response heterogeneity in system behavior. The success of the studies reviewed here often depended upon integration of one or more systems biology approaches with more traditional methods. We hope these examples will inspire a broader range of immunologists to probe questions in a quantitative and integrated manner, advancing collective efforts to understand the immune "system".
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Affiliation(s)
- Rachel A Gottschalk
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Andrew J Martins
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Virginie Sjoelund
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bastian R Angermann
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bin Lin
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ronald N Germain
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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