Figure 4.

(A Upper) Northern blot analysis of GCR1 mRNA abundance. Each lane contains 10 mg of RNA from 4-wk-old wt plants (lane 1) or from three different Arabidopsis T2 plants (lanes 2–4) grown at 21°C under a long-day regime. GCR1 ORF was used as probe. (Lower) Ethidium bromide-stained gel. (B) GTPγ³⁵S-binding assay. Receptor activity was measured in membrane preparations by determining the binding of the nonhydrolyzable GTP analog GTPγ³⁵S. Arabidopsis wt plant (solid bar), GCR1 overexpressing line (hatched bar), and gpa1–2 line, a Gα knockout (open bar).