Figure 2. The split firefly luciferase complementation has a low background in Arabidopsis mesophyll protoplasts.

(A) Only marginal restored luciferase activity could be detected in protoplasts co-expressing individual Aux/IAA-FLucC or ARF C-terminal domain-FLucC (ARFCTD-FLucC) with the unrelated protein MYB30-FLucN. Three biological replicates were conducted for each protein combination and similar interaction patterns were obtained. (B) The 12 Aux/IAAs, the C-terminal domain (CTD) of 8 ARFs, and MYB30 were all expressed in protoplasts when fused with FLucC or FLucN as indicated. Equal amounts of protoplasts (4×10⁴ cells) expressing 20 µg of individual construct for 6 hr were lysed in SDS-PAGE loading buffer. FLucC and FLucN fusion proteins were visualized by western blot using anti-FLucC and anti-FLucN antibodies, respectively. MYB30-FLucN in western blot is marked by an asterisk.