Browsing by Subject "Arabidopsis thaliana"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    High Resolution Transcriptional Profiling and Characterization of Cellular Inclusions in Arabidopsis thaliana Roots Grown in Low Sulfur Conditions
    (2013) Jackson, Terry Lynell

    Environmental stress affects plant development and productivity. Sulfur deficiency is a key nutrient deficiency that adversely affects crop yield. The model plant Arabidopsis thaliana has played an informative role in deciphering the mechanisms involved in sulfur assimilation, as well as, the response to limited conditions. Using Arabidopsis thaliana as a model to investigate gene expression in the root, microarray data sets have been generated. These data sets consist of whole root sections for 6 time points across 72 hours, and enriched populations of 5 radial cell-types and 4 sections of 3 developmental zones of the root at 3 hrs on sulfur limited conditions. With these data it was determined which cellular tissues and developmental zones were affected most by sulfur limited conditions. Furthermore, a novel phenotype was characterized that occurs in roots after growth on low sulfur conditions. Cellular inclusions build up within the cytoplasm of mature cortical root cells. These inclusions have been termed "sulfur pox" and their composition remains to be determined.

  • Thumbnail Image
    ItemOpen Access
    The Arabidopsis thaliana chloroplast division protein FtsZ1 counterbalances FtsZ2 filament stability in vitro.
    (The Journal of biological chemistry, 2021-04) Porter, Katie J; Cao, Lingyan; Chen, Yaodong; TerBush, Allan D; Chen, Cheng; Erickson, Harold P; Osteryoung, Katherine W
    Bacterial cell and chloroplast division are driven by a contractile "Z ring" composed of the tubulin-like cytoskeletal GTPase FtsZ. Unlike bacterial Z rings, which consist of a single FtsZ, the chloroplast Z ring in plants is composed of two FtsZ proteins, FtsZ1 and FtsZ2. Both are required for chloroplast division in vivo, but their biochemical relationship is poorly understood. We used GTPase assays, light scattering, TEM, and sedimentation assays to investigate the assembly behavior of purified Arabidopsis thaliana (At) FtsZ1 and AtFtsZ2 both individually and together. Both proteins exhibited GTPase activity. AtFtsZ2 assembled relatively quickly, forming protofilament bundles that were exceptionally stable, as indicated by their sustained assembly and slow disassembly. AtFtsZ1 did not form detectable protofilaments on its own. When mixed with AtFtsZ2, AtFtsZ1 reduced the extent and rate of AtFtsZ2 assembly, consistent with its previously demonstrated ability to promote protofilament subunit turnover in living cells. Mixing the two FtsZ proteins did not increase the overall GTPase activity, indicating that the effect of AtFtsZ1 on AtFtsZ2 assembly was not due to a stimulation of GTPase activity. However, the GTPase activity of AtFtsZ1 was required to reduce AtFtsZ2 assembly. Truncated forms of AtFtsZ1 and AtFtsZ2 consisting of only their conserved core regions largely recapitulated the behaviors of the full-length proteins. Our in vitro findings provide evidence that FtsZ1 counterbalances the stability of FtsZ2 filaments in the regulation of chloroplast Z-ring dynamics, and suggest that restraining FtsZ2 self-assembly is a critical function of FtsZ1 in chloroplasts.