Figure 4.

Simultaneous Visualization of Pol III and II Transcripts Made by the H1 Promoter

(A) Four H1 promoter-based constructs with the termination signals (T6 for Pol III and pA for Pol II) are indicated. (B) Predicted transcript lengths. (C) Probing of Pol III/II transcripts on northern blot. Total cellular RNA from DNA-transfected HEK293T cells was isolated, and a fixed amount (5 μg) was subjected to northern blotting. The RNA size marker M was used for estimation of the transcript sizes. The rRNAs and tRNAs were stained with ethidium bromide and used as a loading control. The Pol III and Pol II transcripts are indicated (*minor Pol III transcripts of ∼80 nt that likely reflect termination at non-T6 signals; this becomes signal **for construct 4 due to the change in the local sequences). (D) Probing of ∼1,800-nt Pol II transcripts on northern blot. A fixed amount (15 μg) of total RNA was subjected to agarose-formaldehyde gel electrophoresis and northern blotting. The ethidium bromide staining of an RNA ladder was used for the estimation of transcript sizes.