Here we report the cloning and characterization of the Oxytricha granulifera CCTgamma (chaperonin containing tailless complex polypeptide 1) gene encoding a protein that consists of 559 amino acids. The derived amino acid sequence shares 68% identity with Tetrahymena pyriformis CCTgamma and 58% identity with Mus musculus CCTgamma. The O. granulifera CCTgamma gene is located on a 2.07-kbp macronuclear gene-sized piece. Its transcription initiation site was determined by primer extension analysis. The expression of the CCTgamma gene was investigated by northern blot hybridization of the coding region with exponentially growing cells, heat shocked cells, and cells treated with 50 microM CdCl2. After heat shock, a decrease in the amount of the transcript compared to that of exponentially growing cells could be shown. In contrast, higher amounts of the transcript could be detected after treatment with CdCl2.