Fig. 1. alr-1 encodes the C. elegans homolog of Aristaless/ARX. (A) Phylogenetic tree of the homeodomains of Aristaless/ARX family members. The homeodomain sequences were aligned and analyzed using Bonsai 2.1 (http://calliope.gs.washington.edu/software/index.html). The homeodomains of OTD/OTX proteins were used as outliers in this analysis. The frequency at which a particular branch appears in 1000 bootstrap replicates are indicated by hatchmarks: (/) – <50%; (//) – 51-80%; (///) – 81-100%. (B) Alignment of the homeodomains of ALR-1 (Ce), AL (Dm) and ARX (Mm, Hs). Identical residues are indicated in gray. The Q50 residue is boxed. (C) (Top) alr-1 and neighboring predicted open reading frames present on the cosmid R08B4. The orientation of each ORF is indicated by an arrow. Sequences deleted in alr-1(oy42) are indicated by a dashed line; inverted sequences are indicated by a dotted line. (Bottom) Exon/intron structure of alr-1. Sequences encoding the homeodomain are hatched. Sequences deleted in alr-1(ok545) are indicated by a dashed line. Asterisk indicates a point mutation in the first splice donor site in alr-1(oy56). (D) Drosophila Al can functionally substitute for alr-1 in the regulation of odr-7::gfp and ops-1::dsRed expression, and for the dye-filling phenotype. The Al cDNA was expressed under the alr-1 promoter. Adult animals grown at 25°C were examined. n>100 for each.