FIGURE 1.

C. elegans stau-1 is a Staufen homolog. A, exon and intron organization for stau-1 (F55A4.5) and two likely pseudogenes, F55A4.4 and F39E9.7, as deduced from cDNAs. White boxes correspond to 5′- and 3′-UTRs, and gray boxes correspond to coding sequences. Introns are indicated by lines intersecting each exon. All three genes would potentially encode double-stranded RNA-binding proteins, but F55A4.4 and F39E9.7 contain early stop codons according to 5′-RACE analysis. F55A4.4 is SL1 transpliced. Transcripts for F55A4.4 and F39E9.7 are different than reported in WormBase version WS228 (See supplemental Fig. S1). B, protein domain structures for C. elegans STAU-1, Drosophila melanogaster Staufen, and Homo sapiens STAU1. The numbered boxes indicate double-stranded RNA-binding domains. PRD, proline-rich domain. Percentages indicate the percentage of identity and similarity (calculated according to the length of the shortest sequence) between C. elegans STAU-1 and the equivalent domain in the other species. The percentage of identity and similarity is only shown for the second half of domain 2, because there was little similarity for the first half of domain 2. C, a partial phylogenetic tree of Staufen homologs in different species. Full-length protein sequences from selected species were aligned using ClustalW. A phylogenetic tree based on the alignment was generated using the Phylip software package version 3.68.