Fig. 2. Identification of the MAB4/ENP gene. (A) Map-based cloning. The MAB4/ENP locus was mapped to lie between the F3L17 and F10M6 markers on chromosome 4. The number of recombinants are indicated under these markers (recombinant chromosomes/analyzed chromosomes). The mab4-1 mutation is a deletion of 9 bp in At4g31820, which loses three amino acids, G,L and Y. The enp mutation is a point mutation, C to T, which creates a stop codon. In mab4-2 mutants, T-DNA is inserted at the 5' untranslated region of the gene. ARE, auxin-responsive element; WUS, WUS-binding site. (B) The deduced amino acid sequence of MAB4/ENP, shown in comparison with the sequence of NPH3 and RPT2. Asterisks denote residues deleted in the mab4-1 mutant. Black circle indicates the mutated residue in the enp mutant. Gray and black shadings indicate residues identical in the two and three sequences, respectively. (C) Phylogenetic tree of Arabidopsis MAB4/ENP homologs and the two related rice homologs and CPT1. The tree was obtained by the neighbor-joining method using 1000 bootstrap replicates, generated with CLUSTALW. Black circles indicate rice NPH3-like protein.