We cloned two novel members of the CLC chloride channel family from rat and human brain. ClC-6 is a 97-kDa protein, and ClC-7 a 89-kDa protein roughly 45% identical with ClC-6. Together they define a new branch of this gene family. Both genes are very broadly expressed, e.g. in brain, testes, muscle and kidney. In mouse embryos, both genes are expressed as early as day 7. Wyile the human gene for ClC-6 is located on human chromosome 1p36 and shares this region with hClC-Ka and hClC-Kb, ClC-7 is on 16p13. ClC-6 has a highly conserved glycosylation site between transmembrane domains D8 and D9, while ClC-7 is the only known eukaryotic ClC protein which lacks this site. Hydropathy analysis indicates that domain D4 cannot serve as a transmembrane domain. Both ClC-6 and ClC-7 cannot be expressed as chloride channels in Xenopus oocytes, either singly or in combination.
