@article{muhammad_clark_haque_williams_sozzani_long_2022, title={POPEYE intercellular localization mediates cell-specific iron deficiency responses}, volume={8}, ISSN={["1532-2548"]}, url={https://doi.org/10.1093/plphys/kiac357}, DOI={10.1093/plphys/kiac357}, abstractNote={Abstract
               Plants must tightly regulate iron (Fe) sensing, acquisition, transport, mobilization, and storage to ensure sufficient levels of this essential micronutrient. POPEYE (PYE) is an iron responsive transcription factor that positively regulates the iron deficiency response, while also repressing genes essential for maintaining iron homeostasis. However, little is known about how PYE plays such contradictory roles. Under iron-deficient conditions, pPYE:GFP accumulates in the root pericycle while pPYE:PYE–GFP is localized to the nucleus in all Arabidopsis (Arabidopsis thaliana) root cells, suggesting that PYE may have cell-specific dynamics and functions. Using scanning fluorescence correlation spectroscopy and cell-specific promoters, we found that PYE–GFP moves between different cells and that the tendency for movement corresponds with transcript abundance. While localization to the cortex, endodermis, and vasculature is required to manage changes in iron availability, vasculature and endodermis localization of PYE–GFP protein exacerbated pye-1 defects and elicited a host of transcriptional changes that are detrimental to iron mobilization. Our findings indicate that PYE acts as a positive regulator of iron deficiency response by regulating iron bioavailability differentially across cells, which may trigger iron uptake from the surrounding rhizosphere and impact root energy metabolism.}, journal={PLANT PHYSIOLOGY}, publisher={Oxford University Press (OUP)}, author={Muhammad, DurreShahwar and Clark, Natalie M. and Haque, Samiul and Williams, Cranos M. and Sozzani, Rosangela and Long, Terri A.}, year={2022}, month={Aug} }
 @article{crook_willoughby_hazak_okuda_vandermolen_soyars_cattaneo_clark_sozzani_hothorn_et al._2020, title={BAM1/2 receptor kinase signaling drives CLE peptide-mediated formative cell divisions in Arabidopsis roots}, volume={117}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.2018565117}, abstractNote={Significance
          
            Proper elaboration of the plant body plan requires that cell division patterns are coordinated during development in complex tissues. Activation of cell cycle machinery is critical for this process, but it is not clear how or if this links to cell-to-cell communication networks that are important during development. Here we show that key cell divisions that generate the plant root are controlled by cell-to-cell signaling peptides which act through plant-specific receptor kinases to control expression of a specific
            cyclinD
            cell cycle regulatory gene. We show that
            cyclinD
            gene expression depends on both receptor signaling and the SHORT-ROOT transcription factor to ensure timely and robust cell division patterns.
          }, number={51}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Crook, Ashley D. and Willoughby, Andrew C. and Hazak, Ora and Okuda, Satohiro and VanDerMolen, Kylie R. and Soyars, Cara L. and Cattaneo, Pietro and Clark, Natalie M. and Sozzani, Rosangela and Hothorn, Michael and et al.}, year={2020}, month={Dec}, pages={32750–32756} }
 @article{clark_van den broeck_guichard_stager_tanner_blilou_grossmann_iyer-pascuzzi_maizel_sparks_et al._2020, title={Novel Imaging Modalities Shedding Light on Plant Biology: Start Small and Grow Big}, volume={71}, ISSN={1543-5008 1545-2123}, url={http://dx.doi.org/10.1146/annurev-arplant-050718-100038}, DOI={10.1146/annurev-arplant-050718-100038}, abstractNote={ The acquisition of quantitative information on plant development across a range of temporal and spatial scales is essential to understand the mechanisms of plant growth. Recent years have shown the emergence of imaging methodologies that enable the capture and analysis of plant growth, from the dynamics of molecules within cells to the measurement of morphometricand physiological traits in field-grown plants. In some instances, these imaging methods can be parallelized across multiple samples to increase throughput. When high throughput is combined with high temporal and spatial resolution, the resulting image-derived data sets could be combined with molecular large-scale data sets to enable unprecedented systems-level computational modeling. Such image-driven functional genomics studies may be expected to appear at an accelerating rate in the near future given the early success of the foundational efforts reviewed here. We present new imaging modalities and review how they have enabled a better understanding of plant growth from the microscopic to the macroscopic scale. }, number={1}, journal={Annual Review of Plant Biology}, publisher={Annual Reviews}, author={Clark, Natalie M. and Van den Broeck, Lisa and Guichard, Marjorie and Stager, Adam and Tanner, Herbert G. and Blilou, Ikram and Grossmann, Guido and Iyer-Pascuzzi, Anjali S. and Maizel, Alexis and Sparks, Erin E. and et al.}, year={2020}, month={Apr}, pages={789–816} }
 @article{powers_holehouse_korasick_schreiber_clark_jing_emenecker_han_tycksen_hwang_et al._2019, title={Nucleo-cytoplasmic Partitioning of ARF Proteins Controls Auxin Responses in Arabidopsis thaliana}, volume={76}, ISSN={["1097-4164"]}, DOI={10.1016/j.molcel.2019.06.044}, abstractNote={The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development. The auxin response factor (ARF) transcription factor family regulates auxin-responsive gene expression and exhibits nuclear localization in regions of high auxin responsiveness. Here we show that the ARF7 and ARF19 proteins accumulate in micron-sized assemblies within the cytoplasm of tissues with attenuated auxin responsiveness. We found that the intrinsically disordered middle region and the folded PB1 interaction domain of ARFs drive protein assembly formation. Mutation of a single lysine within the PB1 domain abrogates cytoplasmic assemblies, promotes ARF nuclear localization, and results in an altered transcriptome and morphological defects. Our data suggest a model in which ARF nucleo-cytoplasmic partitioning regulates auxin responsiveness, providing a mechanism for cellular competence for auxin signaling.}, number={1}, journal={MOLECULAR CELL}, author={Powers, Samantha K. and Holehouse, Alex S. and Korasick, David A. and Schreiber, Katherine H. and Clark, Natalie M. and Jing, Hongwei and Emenecker, Ryan and Han, Soeun and Tycksen, Eric and Hwang, Ildoo and et al.}, year={2019}, month={Oct}, pages={177-+} }
 @article{clark_buckner_fisher_nelson_nguyen_simmons_balaguer_butler-smith_sheldon_bergmann_et al._2019, title={Stem-cell-ubiquitous genes spatiotemporally coordinate division through regulation of stem-cell-specific gene networks}, volume={10}, ISSN={["2041-1723"]}, DOI={10.1038/s41467-019-13132-2}, abstractNote={AbstractStem cells are responsible for generating all of the differentiated cells, tissues, and organs in a multicellular organism and, thus, play a crucial role in cell renewal, regeneration, and organization. A number of stem cell type-specific genes have a known role in stem cell maintenance, identity, and/or division. Yet, how genes expressed across different stem cell types, referred to here as stem-cell-ubiquitous genes, contribute to stem cell regulation is less understood. Here, we find that, in the Arabidopsis root, a stem-cell-ubiquitous gene, TESMIN-LIKE CXC2 (TCX2), controls stem cell division by regulating stem cell-type specific networks. Development of a mathematical model of TCX2 expression allows us to show that TCX2 orchestrates the coordinated division of different stem cell types. Our results highlight that genes expressed across different stem cell types ensure cross-communication among cells, allowing them to divide and develop harmonically together.}, journal={NATURE COMMUNICATIONS}, author={Clark, Natalie M. and Buckner, Eli and Fisher, Adam P. and Nelson, Emily C. and Nguyen, Thomas T. and Simmons, Abigail R. and Balaguer, Maria A. de Luis and Butler-Smith, Tiara and Sheldon, Parnell J. and Bergmann, Dominique C. and et al.}, year={2019}, month={Dec} }
 @article{spurney_broeck_clark_fisher_balaguer_sozzani_2020, title={tuxnet: a simple interface to process RNA sequencing data and infer gene regulatory networks}, volume={101}, ISSN={["1365-313X"]}, url={https://doi.org/10.1111/tpj.14558}, DOI={10.1111/tpj.14558}, abstractNote={SummaryPredicting gene regulatory networks (GRNs) from expression profiles is a common approach for identifying important biological regulators. Despite the increased use of inference methods, existing computational approaches often do not integrate RNA‐sequencing data analysis, are not automated or are restricted to users with bioinformatics backgrounds. To address these limitations, we developed tuxnet, a user‐friendly platform that can process raw RNA‐sequencing data from any organism with an existing reference genome using a modified tuxedo pipeline (hisat 2 + cufflinks package) and infer GRNs from these processed data. tuxnet is implemented as a graphical user interface and can mine gene regulations, either by applying a dynamic Bayesian network (DBN) inference algorithm, genist, or a regression tree‐based pipeline, rtp‐star. We obtained time‐course expression data of a PERIANTHIA (PAN) inducible line and inferred a GRN using genist to illustrate the use of tuxnet while gaining insight into the regulations downstream of the Arabidopsis root stem cell regulator PAN. Using rtp‐star, we inferred the network of ATHB13, a downstream gene of PAN, for which we obtained wild‐type and mutant expression profiles. Additionally, we generated two networks using temporal data from developmental leaf data and spatial data from root cell‐type data to highlight the use of tuxnet to form new testable hypotheses from previously explored data. Our case studies feature the versatility of tuxnet when using different types of gene expression data to infer networks and its accessibility as a pipeline for non‐bioinformaticians to analyze transcriptome data, predict causal regulations, assess network topology and identify key regulators.}, number={3}, journal={PLANT JOURNAL}, author={Spurney, Ryan J. and Broeck, Lisa and Clark, Natalie M. and Fisher, Adam P. and Balaguer, Maria A. de Luis and Sozzani, Rosangela}, year={2020}, month={Feb}, pages={716–730} }
 @article{balaguer_fisher_clark_fernandez-espinosa_moller_weijers_lohmann_williams_lorenzo_sozzani_et al._2017, title={Predicting gene regulatory networks by combining spatial and temporal gene expression data in Arabidopsis root stem cells}, volume={114}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.1707566114}, abstractNote={Significance
          
            We developed a computational pipeline that uses gene expression datasets for inferring relationships among genes and predicting their importance. We showed that the capacity of our pipeline to integrate spatial and temporal transcriptional datasets improves the performance of inference algorithms. The combination of this pipeline with
            Arabidopsis
            stem cell-specific data resulted in networks that capture the regulations of stem cell-enriched genes in the stem cells and throughout root development. Our combined approach of molecular biology, computational biology, and mathematical biology, led to successful findings of factors that could play important roles in stem cell regulation and, in particular, quiescent center function.
          }, number={36}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Balaguer, M. A. D. and Fisher, A. P. and Clark, N. M. and Fernandez-Espinosa, M. G. and Moller, B. K. and Weijers, D. and Lohmann, J. U. and Williams, C. and Lorenzo, O. and Sozzani, Rosangela and et al.}, year={2017}, month={Sep}, pages={E7632–E7640} }
 @article{clark_hinde_winter_fisher_crosti_blilou_gratton_benfey_sozzani_2016, title={Tracking transcription factor mobility and interaction in Arabidopsis roots with fluorescence correlation spectroscopy}, volume={5}, journal={Elife}, author={Clark, N. M. and Hinde, E. and Winter, C. M. and Fisher, A. P. and Crosti, G. and Blilou, I. and Gratton, E. and Benfey, P. N. and Sozzani, R.}, year={2016} }
 @misc{clark_balaguer_sozzani_2014, title={Experimental data and computational modeling link auxin gradient and development in the Arabidopsis root}, volume={5}, journal={Frontiers in Plant Science}, author={Clark, N. M. and Balaguer, M. A. D. and Sozzani, R.}, year={2014} }