Receptor signal output mediated by the ETR1 N terminus is primarily subfamily I receptor dependent.
etr1-1 is a dominant ethylene receptor gene in Arabidopsis (Arabidopsis thaliana) and confers ethylene insensitivity. The truncated etr1-1(1-349) protein is capable of repressing ethylene responses, whereas etr1(1-349) is not, lending support to a hypothesis that the dominant etr1-1(1-349) could convert wild-type receptors to an ethylene-insensitive state. Assuming that etr1-1(1-349) and etr1(1-349) would share the same signaling mechanism, we hypothesize that the etr1(1-349) protein is capable of repressing ethylene responses when not bound with ethylene. In this study, we show that both etr1(1-349) and etr1-1(1-349) are capable of receptor signal output, which is primarily dependent on subfamily I receptors. The etr1(1-349) and etr1-1(1-349) clones were individually transformed to mutants and the resulting phenotypes were scored. Each of those transgenes restored the rosette growth and flower fertility of etr1-7 ers1-2 to a similar extent. In contrast, neither etr1(1-349) nor etr1-1(1-349) was capable of signal output in etr1-7 ers1-3. The ERS1 transcript was detectable in ers1-2 but not in ers1-3, implying that ETR1 N-terminal signaling is subfamily I dependent. Loss of the subfamily II receptor genes did not perturb etr1-1(1-349)-mediated ethylene insensitivity. Possible roles of subfamily I receptors and disulfide linkages in ETR1 receptor signal output mediated through the N terminus are discussed.
Xie
Fang
F
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
Liu
Qian
Q
Wen
Chi-Kuang
CK
D000483:Alleles; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005030:Ethylenes / Q000378:metabolism*; D005298:Fertility / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D018546:Hypocotyl / Q000254:growth & development / Q000378:metabolism; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D012834:Silver / Q000494:pharmacology
D029681:Arabidopsis Proteins; C095706:ERS protein, Arabidopsis; C494590:ETR1 protein, Arabidopsis; D005030:Ethylenes; D010940:Plant Proteins; D011956:Receptors, Cell Surface; D012834:Silver; C036216:ethylene