Cloning of rabbit Cct6 and the distribution of the Cct complex in mammalian tissues

Cct6 protein is one of the subunits of the Cct complex involved in ATP-depe ndent folding of cellular proteins. We used the cDNA of the human CCT6 subu nit to obtain a full-length cDNA from a rabbit kidney cortex library. Two t ranscripts of 2 and 2.5 kb were detected in rabbit kidney and liver by Nort hern analysis. The rabbit CCT6 was 93% identical to the human gene; the ded uced amino acid sequence was 97% identical. A phylogenetic analysis of Cct6 proteins from mouse, rabbit, human, and yeast showed greater similarities of Cct6 protein among the species than among other Cct subunits. The ATP-bi nding sites were perfectly conserved among mammals and yeast, supporting th e role of Cct complex in ATP-dependent protein folding. Using a polyclonal antibody to human Cct6 protein and Western analysis, we found expression of this subunit in a variety of rabbit organs and tissues, as well as in bovi ne testes, human lymphocytes, human and rabbit reticulocytes, and in two cu ltured kidney cell lines. We also found Cct1 protein by Western analysis in several rabbit organs as well as in bovine testes. These data characterize the rabbit Cct6 subunit and compare it to its homologues, The Western anal yses support the concept that Cct complex is widely distributed among tissu es and highly conserved among eukaryotes. Copyright (C) 2000 S. Karger AG, Baser.