DelGEF, an RCC1-related protein encoded by a gene on chromosome 11p14 critical for two forms of hereditary deafness

We have cloned a human cDNA, DELGEF (deafness locus associated putative guanine nucleotide exchange factor), derived from a 225 kb genomic sequence of chromosome 11p14, critical for the Usher 1C syndrome and for DFNB18, a locus for non-syndromic sensorineural deafness. The amino acid sequence of the protein hDelGEF1 is homologous to the nucleotide exchange factor RCCI for the small GTPase Ran. hDelGEF2 is derived from the same DELGEF gene by alternative splicing. In addition, we have identified a murine homologue, mDelGEF. The ubiquitously expressed soluble protein hDelGEF1 is found both in the cyytoplasm and in the nucleus. Overexpressed hDelGEF2 colocalizes with mitochondria.