Fig. 6. HEN2 protein sequence and similarity of HEN2 to putative DExH-box helicases in diverse eukaryotes. (A) The protein sequence of HEN2. The conserved DExH motifs are marked with double underlines. The sequences were identified according to the Ski2p family consensus as defined by de la Cruz et al. (de la Cruz et al., 1999). The nuclear localization signal is marked with a single underline. The proline to leucine substitution found in the protein encoded by hen2-1 is in bold. (B) A schematic diagram of HEN2 showing the location of the helicase motifs (black bars) and the position of the amino acid substitution in the protein encoded by hen2-1 (asterisk). Below is a list of the homologs from various eukaryotes. The numbers represent percentage identity and similarity (in parentheses) within the respective domains. Within the actual helicase motifs, HEN2 has 95% identity (39/41 amino acids) with the consensus of the proteins listed. At, Arabidopsis thaliana; Hs, Homo sapiens; Dm, Drosophila melanogaster; Sp, Schizosaccharomyces pombe; Sc, Saccharomyces cerevisiae; Ce, Caenorhabditis elegans.