Figure 5.

Expression of the ETR1 N terminus suppresses the CTR1-Nox constitutive ethylene response. A, Scenarios of the ETR1 N-terminal signal mediated by full-length ethylene receptors (black arrows) or full-length ethylene receptor signals mediated by the ETR1 N terminus (red arrows) by an alternative pathway when excess CTR1^7-560 prevents ethylene receptor signaling. B to D, Phenotype (B), hypocotyl length (C), and seedling growth (D) of wild type (Col-0) plants expressing 35S:CTR1^7-560 (designated CTR1-Nox). E, Immunoassay of expression of the CTR1^7-560 fragment in CTR1-Nox lines. F to H, Hypocotyl length (F), seedling growth (G), and rosette phenotype (H) of CTR1-Nox L50 expressing etr1-1^1-349 or etr1^1-349. I, Relative ERF1 expression in CTR1-Nox and CTR1-Nox expressing the ETR1 N terminus. J, Relative transgene expression in the transgene donor (Col-0) and recipient (CTR1-Nox). K, Immunoassay of CTR1^7-560 expression. L6 and L10 indicate the origins of the etr1-1^1-349 and etr1^1-349 transformation lines, respectively. CHEM, The pseudocolor bar indicates relative chemiluminescence strength from weak (dark) to strong (bright); CTR1-Ab, chemiluminescence detected by the monoclonal CTR1 antibody; Immunoblot, staining with Coomassie blue to show relative protein amount; ND, not determined. Data are means ± sd. ** P < 0.01 by Student’s t test. [See online article for color version of this figure.]