Genomic organization of the human and mouse stau genes

Mammalian Staufen is a double-stranded RNA-binding protein potentially invo lved in mRNA transport and localization. Recently, we reported that the hum an gene is located on chromosome 20, region q13.1. We now report the genomi c organization of both the human and mouse stau genes. Amplification of gen omic DNA and sequencing of the resulting PCR products indicated that the hu man and mouse genes are fragmented into 15 and 12 exons, distributed over a t least 65 and 17 kb of genomic DNA, respectively. The three additional exo ns found in the human gene are subjected to differential splicing, generati ng four different transcripts. Corresponding exons have not been found in m ouse transcripts. Apart from those three exons, the overall organization of the stau gene is similar in the two species, and the positions of the exon -intron junctions are perfectly conserved. Even an alternative choice betwe en two splicing acceptor sites, which causes an insertion of 18 nucleotides in exon 5, is conserved in both humans and mice. An extremely G+C-rich reg ion lacking canonical TATA and CAAT boxes was found upstream of the most 5' RACE sequence, suggesting that a housekeeping-like promoter drives the bro ad expression of Staufen in mammalian cells. This work represents the first step toward production of knockout mice and the elucidation of putative St aufen-linked hereditary diseases in humans.