TEP1 binding of hTERT truncations. (A) hTERT
truncations and full-length TEP1 (containing a myc-epitope tag) were
cotransfected into human 293T cells. Cell extracts were
immunoprecipitated by using an anti-flag antibody (to immunoprecipitate
hTERT, bottom) and then analyzed by Western analysis by using anti-myc
antibody to examine coimmunoprecipitation of TEP 1 (top). (B)
Full-length hTERT was synthesized in RRL in the presence of 0.002
μg/μl purified hTER. The lysate alone (no DNA), containing
full-length hTERT (TERT) or containing the RT domain (601–927) was
incubated on ice either alone (alone, lanes 1 and 4), with mock
293T-transfected cell extracts (+mock, lanes 2 and 5), or TEP1 (with a
myc epitope tag) transfected 293T cell extracts (+TEP1, lanes 3 and 6).
The mixtures were then immunoprecipitated with anti-flag antibody and
assayed for telomerase activity (top) and blotted for the presence of
hTERT by using an anti-hTERT antibody (Western blot, middle) and TEP1
by using an anti-myc antibody (Western blot, bottom).