Fig. 1. Structure and conservation of cgh-1. (A) cgh-1 gene structure. The predicted cgh-1 open reading frame (C07H6.5) of 1290 bp contains four exons (black boxes, to scale) and three introns (not to scale). A 3' UTR of approximately 900 bp (not to scale) is predicted by an AAUAAA motif and by cDNA sequences (Y. K., not shown). (B) Conservation of CGH-1. The predicted C. elegans CGH-1 protein is compared with Drosophila ME31B (AAF52881), human RCK (P26196), S. pombe Ste13 (BAA06178), S. cerevisiae DhhIp (NP_010121), a human eIF4-A isoform (NP_001407) and the closest related C. elegans eIF4-A ortholog (F57B9.6). CGH-1 orthologs are designated by a bracket. In each protein a white central box represents the conserved helicase region, with its percentage identity to CGH-1 indicated. Gray boxes indicate less conserved regions, and black boxes shown only in CGH-1 correspond to homology motifs, which are characteristic of RNA helicases (de la Cruz et al., 1999).