Fig. 1.

Expression and sequence analysis of γ-secretase subunits. (A) Transcripts for γ-secretase subunits could be detected in different organs of Arabidopsis thaliana. Reverse transcription was conducted with primers specific to each subunit. mRNA was isolated from diverse organs: seedlings, leaves, and stems. Actin 2 was used as internal standard. (B–E) Sequence alignments of amino acid motifs known from animal studies as crucial for γ-secretase activity and complex assembly. (B) APH-1: GXXXG; (C) Nicastrin: XYXGS; (D) PEN-2: WXXNXXF; (E) Presenilins: NF, YD, GXGD, and PALP motifs; (F) Cladogram created on the basis of amino acid sequence alignment for presenilins.