HALR/ALR SET domains. (A) Schematic representation of ySET1, hTrx/ALL-1, hHALR, and hALR-1. Various known protein motifs are color coded as indicated. (B) Amino acid alignment of SET and post-SET domains of hHALR, hALR, dTrx (accession no. AAF55041), ySET1 (accession no. AAB68867), S. pombe Clr4 (accession no. 060016), hG9a (accession no. S30385), and hSUV39 h1 (accession no. NP_003164). Amino acids conserved among all seven proteins; in hHALR, hALR, dTrx, and ySET1; and in yClr4, hG9a, and hSUV39 h1 are highlighted in red, green, and blue, respectively. Dashes indicate gaps in the alignment. The red and blue lines mark the extent of the SET and post-SET domains, respectively. The conserved block of four residues deleted in HR/SET1Δ is boxed, and the conserved glycine mutated to serine in HR/SET1m1 is marked with an asterisk.