Fig. 4. Structure and patterns of expression of the ALE1 gene. (A) Schematic diagram of the ALE1 gene. White boxes, untranslated exons; gray boxes, translated regions. Positions of three amino acid residues (D, H and S) that are consistently conserved in the catalytic regions of the subtilisin-like serine proteases (the catalytic triad) are indicated (see B,C). The relative positions of the ale1 mutations are shown. (B) Predicted amino acid sequence of the ALE1 protein (accession number: AB060809). A putative signal peptide is underlined. Three residues in the catalytic triad are indicated by asterisks in B and C. (C) Alignments of amino acid sequences around the catalytic triad of subtilisin-like serine proteases. SDD1, A. thaliana; TPP2, human tripeptidyl peptidase 2; BPN’, Bacillus amyloliquefaciens, subtilisin BPN’; KEX2, Saccharomyces cerevisiae; FURIN, human; BLI-4, C. elegans (GenBank accession numbers: T00962, P29144, P00782, KXBY, P09958, and P51559, respectively). (D) The RNA on a gel blot prepared with poly(A)+ RNA from flowers, siliques at various developmental stages, and young plants (plantlets; 12 DAV) was allowed to hybridize with an ALE1 probe that covered part of the tenth exon and the 3' untranslated region. As a control, the washed membrane was subsequently hybridized with a probe for 
-tubulin (TUBA) (lower panel). S, Small siliques 2-4 days after pollination (DAP); M, medium siliques 3-6 DAP; L, large siliques 5-10 DAP.
