FIG. 7.

The sequence F₁₁₂₇KT of hTERT defines the biologically important C-DAT region. (A) Cell lysates (0.2 μg) were prepared from HA5 cells that were stably infected with FLAG-hTERT, vector or hTERT variants with mutations in the +1127 region, and assayed for telomerase activity. HT, heat treated. IS, internal standard. (B) The sequence F₁₁₂₇KT of hTERT is necessary for immortalization of HA5 cells. The last nine amino acids of the various versions of FLAG-hTERT are shown beside the life span of cells expressing these proteins. Amino acids in bold denote changes to primary sequence. The grey box highlights the region necessary for an immortal life span. EL, extended life span.