title: The ARGOS gene family functions in a negative feedback loop to desensitize plants to ethylene.
abstract: BACKGROUND
  Ethylene plays critical roles in plant growth and development, including the regulation of cell expansion, senescence, and the response to biotic and abiotic stresses. Elements of the initial signal transduction pathway have been determined, but we are still defining regulatory mechanisms by which the sensitivity of plants to ethylene is modulated.
  
  
  RESULTS
  We report here that members of the ARGOS gene family of Arabidopsis, previously implicated in the regulation of plant growth and biomass, function as negative feedback regulators of ethylene signaling. Expression of all four members of the ARGOS family is induced by ethylene, but this induction is blocked in ethylene-insensitive mutants. The dose dependence for ethylene induction varies among the ARGOS family members, suggesting that they could modulate responses across a range of ethylene concentrations. GFP-fusions of ARGOS and ARL localize to the endoplasmic reticulum, the same subcellular location as the ethylene receptors and other initial components of the ethylene signaling pathway. Seedlings with increased expression of ARGOS family members exhibit reduced ethylene sensitivity based on physiological and molecular responses.
  
  
  CONCLUSIONS
  These results support a model in which the ARGOS gene family functions as part of a negative feedback circuit to desensitize the plant to ethylene, thereby expanding the range of ethylene concentrations to which the plant can respond. These results also indicate that the effects of the ARGOS gene family on plant growth and biomass are mediated through effects on ethylene signal transduction.
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. muneezarai@gmail.com.|Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan. muneezarai@gmail.com.
authors.forename: Muneeza Iqbal
authors.initials: MI
authors.lastname: Rai
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. xwang39@syr.edu.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. derek.thibault@gmail.com.
authors.forename: Derek M
authors.initials: DM
authors.lastname: Thibault
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. florigen76@gmail.com.
authors.forename: Hyo Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. matthew.bombyk@gmail.com.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Bombyk
authors.affiliation: Department of Biochemistry and Cellular & Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA. bbinder@utk.edu.
authors.forename: Brad M
authors.initials: BM
authors.lastname: Binder
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. snq28@yahoo.com.|Department of Biochemistry, Quaid-i-azam University, Islamabad, 45320, Pakistan. snq28@yahoo.com.
authors.forename: Samina N
authors.initials: SN
authors.lastname: Shakeel
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA. George.E.Schaller@dartmouth.edu.
authors.forename: G Eric
authors.initials: GE
authors.lastname: Schaller
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D005030:Ethylenes / Q000494:pharmacology*; D025461:Feedback, Physiological / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007700:Kinetics; D008954:Models, Biological; D005810:Multigene Family; D009154:Mutation / Q000235:genetics; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D005030:Ethylenes; C036216:ethylene