Fig. 8.

The N-terminal domain of Zmers1b but not Zmetr2b is sufficient to exert dominance in Arabidopsis. Arabidopsis was transformed with the portion of the Zmetr2b coding region representing the N-terminal domain, i.e., Zmetr2b(1-386), to generate lines T:Zmetr2b(1-386) L1, L2, and L3 or transformed with the portion of the Zmers1b coding region representing the N-terminal domain, i.e., Zmers1b(1-350), to generate lines T:Zmers1b(1-350) L1, L2, and L3. Seeds from lines homozygous for Zmetr2b(1-386) (A) or Zmers1b(1-350) (B) were germinated in the dark for 5 days on medium containing 20 μM ACC to assay for their triple response. T:Zmetr2b L9 and T:Zmers1b L11 were included as full-length controls. Wild-type (WT) plants were included as an ethylene sensitive control. ein2-5 and etr1-1 were included as ethylene insensitive controls. Two representative seedlings are shown for each line. Quantitative measurements for hypocotyl and root lengths with standard deviations are shown in Table 4. In (C), RNA was extracted from the same seedlings and Northern analysis performed to detect expression of full-length Zmetr2b or Zmetr2b(1-386) (left top panel), full-length Zmers1b or Zmers1b(1-350) (right top panel), or eEF1A (bottom panels) as an RNA loading control from the same membrane after it had been stripped