The structure and expression of the Salmo salar Ran gene

The Ran protein is a highly conserved GTPase factor of the Res-family of pr oteins. It is involved in the transport of proteins and RNA through the nuc lear pores. cDNA sequences of Ran genes from different organisms are availa ble but no vertebrate genomic sequence as yet. We have isolated a genomic c osmid clone of the Ran1 gene of Atlantic salmon (Salmo salar) and found tha t the gene is about 2.2 kb and has got 5 introns. Its gene structure was co mpared to those of Caenorhabditis elegans and Arabidopsis thaliana and one intron was found to be conserved in position. Two different Ran transcripts were identified in salmon, indicating that there are two Ran genes, Ran1 a nd Ran2. Both transcripts were found in all ten salmon tissues tested, thou gh Ran1 to a higher degree.