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Status |
Public on Dec 01, 2018 |
Title |
HSFA2 functions in the physiological adaptation of undifferentiated plant cells to spaceflight microgravity environment. |
Organism |
Arabidopsis thaliana |
Experiment type |
Expression profiling by array
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Summary |
The Heat Shock Factor A2 (HsfA2), as a part of the HSF network, is essential to the plant’s response to almost any environmental stress and to the cellular homeostatic control mechanisms. Plant cell cultures disabled in HsfA2 function were grown aboard the International Space Station (ISS) in order to ascertain whether or not they use the same terrestrially effective systems to adapt to the novel environment of spaceflight. Cultured lines of Arabidopsis thaliana derived from wild type (WT) cultivar Col-0 and from a knock-out line deficient in the gene encoding HSFA2 (HSFA2 KO) were launched to the ISS on SpaceX-2 as part of the Cellular Expression Logic (CEL) experiment of the BRIC17 spaceflight mission and were fixed in-flight after 10 days on orbit. Microarray gene expression data were analyzed using a two-part comparative approach. First, differentially expressed genes were identified between the environments (spaceflight to ground) within cells of the same genotype, which represented physiological adaptation to the spaceflight environment. Second, gene expression profiles were identified between the genotypes (HSFA2 KO to WT) within the same environment, defining genes uniquely required by the two genotypes in the ground and spaceflight adapted states. The physiological state of the cells as a result of disabling a gene has tremendous control over the mechanisms induced to adapt to the environment of spaceflight. The HsfA2 demonstrated a role in the physiological adaptation to the spaceflight environment since the cells disabled in the HsfA2 gene used substantially different genes to achieve the spaceflight adapted state than the WT cells. The endoplasmic reticulum (ER) stress and unfolded protein response (UPR) define the HSFA2 KO cells’ physiological state regardless of the environment and likely result from the deficiency in the chaperone-mediated protein folding machinery. HsfA2 seems to have a universal stress response role but also specific roles in the physiological adaptation to spaceflight through cell wall remodeling, signal perception and transduction and starch biosynthesis. Implementation of knock-out cells identified a set of genes with a required expression level in order for a cell to achieve a spaceflight-adapted state. The HSFA2 KO cells helped to unravel the HsfA2-dependent genes of the adaption of wild type cells to the environment of spaceflight.
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Overall design |
The CEL (Cellular Expression Logic) experiment setup and organization was a modification of a previous Arabidopsis cell culture experiment in BRIC16 (Paul, Zupanska et al. 2012). The CEL BRIC17 experiment was launched on board the Dragon capsule of SpaceX-3 CRS mission to the International Space Station (ISS) on the 1st of March 2013. The cultured cell lines (both the ground control and the spaceflight samples) were grown within 60mm Petri plates in Petri Dish Fixation Units (PDFUs) that were housed within the Biological Research In Canister (BRIC) hardware. Two BRIC containers (A and B) were assigned to CEL within the BRIC17 payload. Each chamber housed 5 PDFUs, each PDFU holding one 60mm Petri plate. In each BRIC container there were 2 plates with wild type (WT) cells and 3 plates with knock-out cells of two genotypes. The exact same PDFU composition was recapitulated in BRICs on the ground in the ISS Environmental Simulator (ISSES) chamber at Kennedy Space Center (KSC) as Ground Controls. The Ground Controls were initiated with a 48 hrs delay so that the precise temperature environment of the ISS could be recreated for the ground controls in the ISSES chamber. Cells were fixed in-flight in RNAlater on the 10th day on orbit, and the ground controls were fixed 48 hours later. RNAlater fixation was initiated by the crew using an activation tool that moves RNAlater from a storage container in the PDFU into the Petri Plate. Twenty four hours after fixation, the entire BRIC was moved to the MELFI (Minus Eighty-degree Laboratory Freezer for ISS) where it resided until cold stowage transport back to Earth within the Dragon capsule. After returning to Earth the samples were reclaimed at KSC, and then transported to the University of Florida (UF) laboratories. The total RNA was extracted from spaceflight samples and corresponding Ground Control samples and subjected to microarrays.
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Contributor(s) |
Zupanska AK, Ferl RJ, LeFrois CE, Paul A |
Citation(s) |
30658467 |
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Submission date |
Feb 27, 2017 |
Last update date |
Feb 15, 2019 |
Contact name |
Robert J. Ferl |
E-mail(s) |
ferllabuf@gmail.com
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Phone |
352-273-8030
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Organization name |
University of Florida
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Department |
Horticultural Sciences
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Lab |
Ferl's lab
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Street address |
1301 Fifield Hall PO Box 110690
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City |
Gainesville |
State/province |
Florida |
ZIP/Postal code |
32611 |
Country |
USA |
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Platforms (1) |
GPL198 |
[ATH1-121501] Affymetrix Arabidopsis ATH1 Genome Array |
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Samples (16)
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Relations |
BioProject |
PRJNA376871 |