Browsing by Author "Nemhauser, Jennifer L."

Now showing 1 - 5 of 5
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    Accelerating structure-function mapping using the ViVa webtool to mine natural variation
    Hamm, Morgan; Moss, Britney; Leydon, Alexander; Gala, Hardik; Lanctot, Amy; Ramos, Román; Klaeser, Hannah; Lemmex, Andrew; Zahler, Mollye; Nemhauser, Jennifer L.; Wright, R. Clay (Wiley, 2018-12-05)
    Thousands of sequenced genomes are now publicly available capturing a significant amount of natural variation within plant species; yet, much of this data remains inaccessible to researchers without significant bioinformatics experience. Here, we present a webtool called ViVa (Visualizing Variation) which aims to empower any researcher to take advantage of the amazing genetic resource collected in the Arabidopsis thaliana 1001 Genomes Project (http://1001genomes.org). ViVa facilitates data mining on the gene, gene family or gene network level. To test the utility and accessibility of ViVa, we assembled a team with a range of expertise within biology and bioinformatics to analyze the natural variation within the well-studied nuclear auxin signaling pathway. Our analysis has provided further confirmation of existing knowledge and has also helped generate new hypotheses regarding this well studied pathway. These results highlight how natural variation could be used to generate and test hypotheses about less studied gene families and networks, especially when paired with biochemical and genetic characterization. ViVa is also readily extensible to databases of interspecific genetic variation in plants as well as other organisms, such as the 3,000 Rice Genomes Project (http://snp-seek.irri.org/) and human genetic variation (https://www.ncbi.nlm.nih.gov/clinvar/).
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    Characterizing Auxin Response Circuits in Saccharomyces cerevisiae by Flow Cytometry
    Pierre-Jerome, Edith; Wright, R. Clay; Nemhauser, Jennifer L. (2017-01)
    Recapitulation of the nuclear auxin response pathway in Saccharomyces cerevisiae (yeast) provides a means to functionally assay the contribution of individual signaling components to response dynamics. Here, we describe a time course assay for characterizing auxin response circuits using flow cytometry. This method allows for quantitative measurements of the dynamic response of up to 12 circuits (strains) at once. We also describe a steady-state assay and how to utilize an R package we developed to facilitate data analysis.
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    Insights into the Evolution and Function of Auxin Signaling F-Box Proteins in Arabidopsis thaliana Through Synthetic Analysis of Natural Variants
    Wright, R. Clay; Zahler, Mollye L.; Gerben, Stacey R.; Nemhauser, Jennifer L. (2017-10)
    The evolution of complex body plans in land plants has been paralleled by gene duplication and divergence within nuclear auxin-signaling networks. A deep mechanistic understanding of auxin signaling proteins therefore may allow rational engineering of novel plant architectures. Toward that end, we analyzed natural variation in the auxin receptor F-box family of wild accessions of the reference plant Arabidopsis thaliana and used this information to populate a structure/function map. We employed a synthetic assay to identify natural hypermorphic F-box variants and then assayed auxin-associated phenotypes in accessions expressing these variants. To more directly measure the impact of the strongest variant in our synthetic assay on auxin sensitivity, we generated transgenic plants expressing this allele. Together, our findings link evolved sequence variation to altered molecular performance and auxin sensitivity. This approach demonstrates the potential for combining synthetic biology approaches with quantitative phenotypes to harness the wealth of available sequence information and guide future engineering efforts of diverse signaling pathways.
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    New tangles in the auxin signaling web
    Wright, R. Clay; Nemhauser, Jennifer L. (2015-01)
    Plants use auxin to relay critical information that shapes their growth and development. Auxin perception and transcriptional activation are mediated by the degradation of Aux/IAA repressor proteins. Degradation of Aux/IAAs relieves repression on Auxin Response Factors (ARFs), which bind DNA sequences called Auxin Response Elements (AuxREs). In most higher plant genomes, multiple paralogs exist for each part of the auxin nuclear signaling pathway. This potential combinatorial diversity in signaling pathways likely contributes to the myriad of context-specific responses to auxin. Recent structures of several domains from ARF proteins have exposed new modes of ARF dimerization, new models for ARF-AuxRE specificity, and the strong likelihood of larger order complexes formed by ARF and Aux/IAA homo- and heteromultimerization. Preliminary experiments support a role for these novel interactions in planta, further increasing the potential architectural complexity of this seemingly simple pathway.
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    Plant Synthetic Biology: Quantifying the Known Unknowns and Discovering the Unknown Unknowns
    Wright, R. Clay; Nemhauser, Jennifer L. (2019-01-10)