Interferon-Inducible IFI16, a Negative Regulator of Cell Growth, Down-Regulates Expression of Human Telomerase Reverse Transcriptase (hTERT) Gene
Figure 3
IFI16 inhibits c-Myc-stimulated transcription and hTERT expression in HeLa cells.
(A) Total protein extracts prepared from HeLa cells infected with control retrovirus (lane 1) or a virus encoding IFI16 protein (lane 2) were subjected to immunoblotting using antibodies specific to the indicated proteins. (B) Sub-confluent cultures of HeLa cells were transfected with pMyc-TA-luc reporter plasmid (1.0 µg) along with a second pRL-TK reporter plasmid (0.2 µg) and an empty plasmid (pCMV; column 1), a plasmid encoding c-Myc (column 2 and 4), a plasmid encoding IFI16 (column 3), or both plasmids encoding c-Myc and increasing amounts of the plasmid encoding IFI16 protein (column 5 and 6). After 44–48 h of transfections, cells were lysed and the lysates were analyzed for dual luciferase activity. Normalized relative luciferase activity in control cells is indicated as 1.0. (C) Total protein extracts prepared from HeLa cells infected with control retrovirus (lane 1) or a virus encoding antisense to IFI16 mRNA (lanes 2) were subjected to immunoblotting using antibodies specific to the indicated proteins.