FIG. 4.

Processing, accumulation, and activity of a chimeric hTR-U64 RNA. (A) Northern blot analysis of total RNA prepared from cells transiently transfected with the following constructs: sequence-tagged AT SE (solid arrowheads), AT hTR-U64, and WT hTR-U64 (open arrowhead). The blot was probed with h4 and h5 oligonucleotides. Lane i contains in vitro-transcribed hTR E and N and chimeric hTR-U64 RNA standards. (B) TRAP activity assay of extracts prepared from transiently transfected 293 cells. Oligonucleotides amplifying WT (C₃TA₂) or AT (A₂C₄, C₂A₂C₂) telomerase extension products were used as indicated. Each pair of lanes corresponds to 5- and 25-fold dilutions of whole-cell extracts.