Witnessing the evolution of transcription in mitochondria: the mitochondrial genome of the primitive brown alga Pylaiella littoralis (L.) Kjellm. Encodes a T7-like RNA polymerase

J Mol Biol. 1998 Apr 17;277(5):1047-57. doi: 10.1006/jmbi.1998.1679.

Abstract

A region of the mitochondrial genome of the primitive brown alga Pylaiella littoralis containing a plasmid-like insert which contains a transcribed T7-phage-type RNA polymerase gene is described. This is a first report of a phage-type RNA polymerase gene integrated in a mitochondrial genome. As the mitochondrial genome of this alga also contains sigma-70 proteobacterial promoter regions, i.e. traces of the ancestral alpha2betabeta'sigma-70 proteobacterial RNA polymerase, this genome witnesses two types of RNA polymerases. As such the mitochondrial genome of P. littoralis represents a unique stage in the evolution of transcription in mitochondria, which contrasts with that of the primitive protist Reclinomonas americana, which still retains the ancestral alpha2betabeta'sigma-70 proteobacterial RNA polymerase genes, and with animals, land plants and fungi, which use phage-type polymerases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromosome Mapping
  • Cloning, Molecular
  • DNA, Mitochondrial / genetics
  • DNA-Directed RNA Polymerases / chemistry*
  • Eukaryota / enzymology*
  • Evolution, Molecular
  • Mitochondria / genetics*
  • Models, Genetic
  • Phylogeny
  • Plasmids / genetics
  • Promoter Regions, Genetic / genetics
  • RNA, Messenger / analysis
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Transcription, Genetic / genetics

Substances

  • DNA, Mitochondrial
  • RNA, Messenger
  • DNA-Directed RNA Polymerases

Associated data

  • GENBANK/AF034976