FIG. 1.

Coimmunoprecipitation of h-mtTFB1 and h-mtTFA from a transcriptionally active mitochondrial lysate from HeLa cells. A soluble HeLa cell mitochondrial extract was prepared that efficiently initiated transcription from a linear DNA template containing the human LSP (top panel). The lysate (undepleted, lane 1) produced a specific radiolabeled runoff transcript (labeled LSP) that was visualized by autoradiography. Transcription activity was also assayed from lysates that were immunodepleted with affinity-purified h-mtTFB1 antibody (h-mtTFB1 depleted, lane 3) or a control affinity-purified preimmune serum (pre-immune depleted, lane 2). Western immunoblot analysis of the corresponding extracts with an antibody to h-mtTFB1 (middle panel) or h-mtTFA (bottom panel) is also shown.