A candidate gene for RNA export carrier protein has two RBDs (RNA binding domain and Ran binding domain)

The human Ras-related nuclear protein Ran/TC4 is the member of a well conserved family of GTPases that can regulate cell-cycle progression, nuclear structure, protein import, and RNA export through nuclear pore complex (NPC). Translocation of RNA through the NPC also needs a RNA-binding protein as a possible mediator of export. By a low-stringency hybridization with a PCR fragment encoding RNA-binding domain as a probe, we obtained a partial human cDNA from skeletal muscle cDNA library. The deduced amino acid sequence indicated that the gene possessed both RNA-binding domain and Ran-binding domain, therefore it is a candidate gene for RNA export carrier protein. RNA blot analysis showed that this gene appeared approximately 8-10 kilo base in length and that the gene expression level in several human tissues is ubiquitous. The function of the gene will be discussed.