Related Experiment Video
Updated: Aug 12, 2026

Simultaneous Mapping and Quantitation of Ribonucleotides in Human Mitochondrial DNA
Published on: November 14, 2017
Preference of human mitochondrial RNA polymerase for superhelical templates with mitochondrial promoters
1Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110.
Abstract:
The RNA polymerase of HeLa cell mitochondria has been purified free of endonuclease and DNA topoisomerase activities, permitting evaluation of the effect of template topology on transcription in vitro. On single-stranded DNA templates, transcription is nonspecific and does not require mitochondrial DNA sequences. In contrast, duplex DNA templates are efficiently transcribed only when they (1) carry the mitochondrial D-loop region and (2) are negatively supercoiled. These findings suggest a role for template superhelicity in modulating mitochondrial transcription in vivo.
Related Concept Videos
Animal Mitochondrial Genetics
Bacterial RNA Polymerase
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...
Mitochondrial Precursor Proteins
Most of the mitochondrial precursors...
Bacterial Transcription
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Eukaryotic RNA Polymerases
All three eukaryotic RNAPs require specific transcription factors, of which the...

