Figure 4.

Alternative splicing and RNA editing of Rdl affect GABA potency. a, Representative current responses of RDL expressed in Xenopus oocytes to GABA at concentrations from 1 μm to 3 mm. b, Example concentration–response curves of two RDL edit isoforms in ac and bd splice backgrounds. c, The graph shows GABA EC₅₀ values of all possible editing isoforms as mean ± SEM (n = 3–7 oocytes, each oocyte from a different animal), ordered from left to right according to the EC₅₀ values for the bd splice variant. All the actual EC₅₀ values are listed in Table 3, and the two concentration–response curves giving the extreme EC₅₀ values in the bd splice variant are shown in Figure 4b. EC₅₀ values of edit isoforms found to exist in vivo through clone analysis (Fig. 3) are marked by an asterisk. Closed squares, ac variant; open squares, bd variant. d, Splice/edit isoforms can show variation in current response to the same GABA concentration (4 mm).