- Telomerase activity is repressed during differentiation along the hepatocytic and biliary epithelial lineages: verification on immortal cell lines from the same origin. Fukutomi, M., Enjoji, M., Iguchi, H., Yokota, M., Iwamoto, H., Nakamuta, M., Sakai, H., Nawata, H. Cell Biochem. Funct. (2001)