Browsing by keyword "Gene Expression Regulation, Plant"

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    • Characterization of THB1, a Chlamydomonas reinhardtii truncated hemoglobin: linkage to nitrogen metabolism and identification of lysine as the distal heme ligand
      Johnson, Eric A.; Rice, Selena L.; Preimesberger, Matthew R.; Nye, Dillon B.; Gilevicius, Lukas; Wenke, Belinda B.; Brown, Jason; Witman, George B.; Lecomte, Juliette T. J. (2014-07-22)
      The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added ligand, THB1 coordinates the heme iron with the canonical proximal histidine and a distal lysine. In the cyanomet state, THB1 is structurally similar to other known truncated hemoglobins, particularly the heme domain of Chlamydomonas eugametos LI637, a light-induced chloroplastic hemoglobin. Recombinant THB1 is capable of binding nitric oxide (NO(*)) in either the ferric or ferrous state and has efficient NO(*) dioxygenase activity. By using different C. reinhardtii strains and growth conditions, we demonstrate that the expression of THB1 is under the control of the NIT2 regulatory gene and that the hemoglobin is linked to the nitrogen assimilation pathway.

    • Enhanced Y1H assays for Arabidopsis
      Gaudinier, Allison; Zhang, Lifang; Reece-Hoyes, John S.; Taylor-Teeples, Mallorie; Pu, Li; Liu, Zhijie; Breton, Ghislain; Pruneda-Paz, Jose L.; Kim, Dahae; Kay, Steve A.; et al. (2011-10-30)
      We present an Arabidopsis thaliana full-length transcription factor resource of 92% of root stele-expressed transcription factors and 74.5% of root-expressed transcription factors. We demonstrate its use with enhanced yeast one-hybrid (eY1H) screening for rapid, systematic mapping of plant transcription factor-promoter interactions. We identified 158 interactions with 13 stele-expressed promoters, many of which occur physically or are regulatory in planta.

    • Patellin1, a novel Sec14-like protein, localizes to the cell plate and binds phosphoinositides
      Peterman, T. Kaye; Ohol, Yamini M.; McReynolds, Lisa J.; Luna, Elizabeth J. (2004-10-07)
      Membrane trafficking is central to construction of the cell plate during plant cytokinesis. Consequently, a detailed understanding of the process depends on the characterization of molecules that function in the formation, transport, targeting, and fusion of membrane vesicles to the developing plate, as well as those that participate in its consolidation and maturation into a fully functional partition. Here we report the initial biochemical and functional characterization of patellin1 (PATL1), a novel cell-plate-associated protein that is related in sequence to proteins involved in membrane trafficking in other eukaryotes. Analysis of the Arabidopsis genome indicated that PATL1 is one of a small family of Arabidopsis proteins, characterized by a variable N-terminal domain followed by two domains found in other membrane-trafficking proteins (Sec14 and Golgi dynamics domains). Results from immunolocalization and biochemical fractionation studies suggested that PATL1 is recruited from the cytoplasm to the expanding and maturing cell plate. In vesicle-binding assays, PATL1 bound to specific phosphoinositides, important regulators of membrane trafficking, with a preference for phosphatidylinositol(5)P, phosphatidylinositol(4,5)P(2), and phosphatidylinositol(3)P. Taken together, these findings suggest a role for PATL1 in membrane-trafficking events associated with cell-plate expansion or maturation and point to the involvement of phosphoinositides in cell-plate biogenesis.