Identification of a novel member of the CLIC family, CLIC6, mapping to 21q22.12.

Five members of the newly identified chloride intracellular channel (CLIC) gene family of intracellular chloride channels (CLIC1-CLIC5) have previously been described in humans. Here we report the molecular cloning and initial characterisation of two splice forms of a novel member of this family, CLIC6, mapping to human chromosome 21. Two essential features distinguish CLIC6 from other members of the family. The CLIC6 protein is significantly longer and the CLIC6 gene contains a GC rich segment, which encodes a 10 amino acid motif repeated 14 times in the amino-terminus. Surprisingly, the repeat is conserved in the lagomorphs, but not in the rodents lineage. The putative bovine orthologue of CLIC5, p64, also exhibits a repeated motif, which is different from that of CLIC6. Attempts to functionally characterise CLIC6 by voltage clamp failed to show any chloride channel activity. Hence, the exact function of this protein remains unknown.