Human mitochondrial transcription factor A and promoter spacing integrity are required for transcription initiation

Biochim Biophys Acta. 1995 May 24;1271(1):127-34. doi: 10.1016/0925-4439(95)00019-z.


The two major promoters for transcription of the human mitochondrial genome are located near each other in the displacement-loop region of the molecule. Previous work has localized these promoters to regions of < 100 nucleotides each; the DNA sequence at the transcription start site is stringently required, as is the region from -10 to -40 base pairs upstream of each respective start site. Each upstream site is recognized and bound by human mitochondrial transcription factor A (h-mtTFA), an event previously shown to be important for transcriptional activation. We report here results using recombinant h-mtTFA that demonstrate the dependence of transcription initiation of h-mtTFA. In addition, altering the distance between the h-mtTFA binding site and the transcription start site greatly impairs transcription initiation efficiency. The decrease in transcription initiation efficiency was shown to be a consequence of altering the position of h-mtTFA binding as opposed to the strength of h-mtTFA binding, as judged by DNA footprinting ability. Analysis of a chimeric yeast-human promoter revealed that the yeast mtTFA homologue cannot substitute for the human protein, even when bound at an appropriate position upstream of the human transcription start site.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Composition
  • Base Sequence
  • Chimera
  • Cloning, Molecular
  • DNA Replication*
  • DNA, Mitochondrial / biosynthesis*
  • DNA, Mitochondrial / metabolism*
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / isolation & purification
  • DNA-Binding Proteins / metabolism*
  • DNA-Directed RNA Polymerases / metabolism
  • Deoxyribonuclease I
  • Escherichia coli
  • Gene Expression
  • Humans
  • KB Cells
  • Mitochondrial Proteins*
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Nuclear Proteins*
  • Promoter Regions, Genetic*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Templates, Genetic
  • Transcription Factors / biosynthesis
  • Transcription Factors / isolation & purification
  • Transcription Factors / metabolism*
  • Transcription, Genetic*


  • DNA, Mitochondrial
  • DNA-Binding Proteins
  • Mitochondrial Proteins
  • Nuclear Proteins
  • Recombinant Proteins
  • TFAM protein, human
  • Transcription Factors
  • mitochondrial transcription factor A
  • DNA-Directed RNA Polymerases
  • Deoxyribonuclease I