Figure 5.

Mutation sites in AFB proteins and SGT1b that confer resistance to picolinate auxins. A, Relative positions of the mutations conferring auxin resistance in the polypeptide sequences of AFB5 (this work) and TIR1 (Ruegger et al., 1998; Alonso et al., 2003) were determined by alignment using Clustal within the Vector NTI suite (see Supplemental Fig. S2). The F-box domain is denoted in gray. Note that AFB5 contains a 46-residue N-terminal extension relative to TIR1. A similar length N-terminal extension is also found in AFB4, but not in the four AFBs associated with the IAA and 2,4-D response (Dharmasiri et al., 2005b). B, Exons of SGT1b are shown as boxed regions. Sites of mutations occur at the 3′ splicing site of intron 6 in sgt1b-5 and intron 7 in sgt1b-4 and sgt1b-6 of the gene. The nucleotide sequences of the 3′ intron-exon boundaries are shown. The intron portion is shaded gray and the mutation sites are arrowed.