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Full-Text Articles in Biology
Evolution Acts On Enhancer Organization To Fine-Tune Gradient Threshold Readouts, Justin Crocker, Yoichiro Tamori, Albert Erives
Evolution Acts On Enhancer Organization To Fine-Tune Gradient Threshold Readouts, Justin Crocker, Yoichiro Tamori, Albert Erives
Dartmouth Scholarship
The elucidation of principles governing evolution of gene regulatory sequence is critical to the study of metazoan diversification. We are therefore exploring the structure and organizational constraints of regulatory sequences by studying functionally equivalent cis-regulatory modules (CRMs) that have been evolving in parallel across several loci. Such an independent dataset allows a multi-locus study that is not hampered by nonfunctional or constrained homology. The neurogenic ectoderm enhancers (NEEs) of Drosophila melanogaster are one such class of coordinately regulated CRMs. The NEEs share a common organization of binding sites and as a set would be useful to study the relationship …
The Leaf Ionome As A Multivariable System To Detect A Plant's Physiological Status, Ivan R. Baxter, Olga Vitek, Brett Lahner, Balasubramaniam Muthukumar, Monica Borghi, Joe Morrissey, Mary Lou Guerinot, David E. Salt
The Leaf Ionome As A Multivariable System To Detect A Plant's Physiological Status, Ivan R. Baxter, Olga Vitek, Brett Lahner, Balasubramaniam Muthukumar, Monica Borghi, Joe Morrissey, Mary Lou Guerinot, David E. Salt
Dartmouth Scholarship
The contention that quantitative profiles of biomolecules contain information about the physiological state of the organism has motivated a variety of high-throughput molecular profiling experiments. However, unbiased discovery and validation of biomolecular signatures from these experiments remains a challenge. Here we show that the Arabidopsis thaliana (Arabidopsis) leaf ionome, or elemental composition, contains such signatures, and we establish statistical models that connect these multivariable signatures to defined physiological responses, such as iron (Fe) and phosphorus (P) homeostasis. Iron is essential for plant growth and development, but potentially toxic at elevated levels. Because of this, shoot Fe concentrations are …
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Dartmouth Scholarship
Photosynthesis, heme biosynthesis, and Fe-S cluster assembly all take place in the chloroplast, and all require iron. Reduction of iron via a membrane-bound Fe(III) chelate reductase is required before iron transport across membranes in a variety of systems, but to date there has been no definitive genetic proof that chloroplasts have such a reduction system. Here we report that one of the eight members of the Arabidopsis ferric reductase oxidase (FRO) family, FRO7, localizes to the chloroplast. Chloroplasts prepared from fro7 loss-of-function mutants have 75% less Fe(III) chelate reductase activity and contain 33% less iron per microgram of chlorophyll than …
Revisiting A Model Of Ontogenetic Growth: Estimating Model Parameters From Theory And Data, Melanie E. Moses, Chen Hou, William H. Woodruff, Geoffrey B. West, Jeffery C. Nekola, Wenyun Zuo, James H. Brown
Revisiting A Model Of Ontogenetic Growth: Estimating Model Parameters From Theory And Data, Melanie E. Moses, Chen Hou, William H. Woodruff, Geoffrey B. West, Jeffery C. Nekola, Wenyun Zuo, James H. Brown
Biological Sciences Faculty Research & Creative Works
The ontogenetic growth model (OGM) of West et al. provides a general description of how metabolic energy is allocated between production of new biomass and maintenance of existing biomass during ontogeny. Here, we reexamine the OGM, make some minor modifications and corrections, and further evaluate its ability to account for empirical variation on rates of metabolism and biomass in vertebrates both during ontogeny and across species of varying adult body size. We show that the updated version of the model is internally consistent and is consistent with other predictions of metabolic scaling theory and empirical data. The OGM predicts not …
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Systems Approach Identifies An Organic Nitrogen-Responsive Gene Network That Is Regulated By The Master Clock Control Gene Cca1, Rodrigo A. Gutierrez, Trevor L. Stokes, Karen Thum, Xiaodong Xu, Mariana Obertello, Manpreet S. Katari, Milos Tanurdzic, Alexis Dean, Damion C. Nero, C Robertson Mcclung, Gloria M. Coruzzi
Dartmouth Scholarship
Understanding how nutrients affect gene expression will help us to understand the mechanisms controlling plant growth and development as a function of nutrient availability. Nitrate has been shown to serve as a signal for the control of gene expression in Arabidopsis. There is also evidence, on a gene-by-gene basis, that downstream products of nitrogen (N) assimilation such as glutamate (Glu) or glutamine (Gln) might serve as signals of organic N status that in turn regulate gene expression. To identify genome-wide responses to such organic N signals, Arabidopsis seedlings were transiently treated with ammonium nitrate in the presence or absence of …
Functional Live-Cell Imaging Demonstrates That Beta1-Integrin Promotes Type Iv Collagen Degradation By Breast And Prostate Cancer Cells., Mansoureh Sameni, Julie Dosescu, Kenneth M. Yamada, Dora Cavallo-Medved, Bonnie F. Sloane
Functional Live-Cell Imaging Demonstrates That Beta1-Integrin Promotes Type Iv Collagen Degradation By Breast And Prostate Cancer Cells., Mansoureh Sameni, Julie Dosescu, Kenneth M. Yamada, Dora Cavallo-Medved, Bonnie F. Sloane
Biological Sciences Publications
The ability of tumor cells to adhere to, migrate on, and remodel extracellular matrices is mediated by cell surface receptors such as beta1-integrins. Here we conducted functional live-cell imaging in real time to investigate the effects of modulating beta1-integrin expression and function on proteolytic remodeling of the extracellular matrix. Human breast and prostate cancer cells were grown on reconstituted basement membrane containing a quenched fluorescent form of collagen IV. Generation of cleavage products and the resulting increases in fluorescence were imaged and quantified. Decreases in the expression and activity of beta1-integrin reduced digestion of quenched fluorescent-collagen IV by the breast …
Caveolin-1-Mediated Expression And Secretion Of Kallikrein 6 In Colon Cancer Cells., Rebecca S. Henkhaus, Upal Kunal Basu Roy, Dora Cavallo-Medved, Bonnie F. Sloane
Caveolin-1-Mediated Expression And Secretion Of Kallikrein 6 In Colon Cancer Cells., Rebecca S. Henkhaus, Upal Kunal Basu Roy, Dora Cavallo-Medved, Bonnie F. Sloane
Biological Sciences Publications
Kallikreins are secreted proteases that may play a functional role and/or serve as a serum biomarker for the presence or progression of certain types of cancers. Kallikrein 6 (KLK6) has been shown to be upregulated in several types of cancers, including colon. The aims of this study were to elucidate pathways that influence KLK6 gene expression and KLK6 protein secretion in the HCT116 human colon cancer cells. Our data indicate a central role for caveolin-1 (CAV-1), the main structural protein of caveolae, in both KLK6 gene expression and protein secretion. Sucrose gradient subcellular fractionation reveals that CAV-1 and KLK6 colocalize …