Intervening sequences in an Archaea DNA polymerase gene

Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5577-81. doi: 10.1073/pnas.89.12.5577.


The DNA polymerase gene from the Archaea Thermococcus litoralis has been cloned and expressed in Escherichia coli. It is split by two intervening sequences (IVSs) that form one continuous open reading frame with the three polymerase exons. To our knowledge, neither IVS is similar to previously described introns. However, the deduced amino acid sequences of both IVSs are similar to open reading frames present in mobile group I introns. The second IVS (IVS2) encodes an endonuclease, I-Tli I, that cleaves at the exon 2-exon 3 junction after IVS2 has been deleted. IVS2 self-splices in E. coli to yield active polymerase, but processing is abolished if the IVS2 reading frame is disrupted. Silent changes in the DNA sequence at the exon 2-IVS2 junction that maintain the original protein sequence do not inhibit splicing. These data suggest that protein rather than mRNA splicing may be responsible for production of the mature polymerase.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Archaea / enzymology
  • Archaea / genetics*
  • Base Sequence
  • Chromosome Deletion
  • DNA-Directed DNA Polymerase / genetics*
  • DNA-Directed DNA Polymerase / metabolism
  • Escherichia coli / genetics
  • Exons
  • Genes, Bacterial*
  • Humans
  • Introns*
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Open Reading Frames
  • Plasmids
  • Recombinant Proteins / metabolism
  • Restriction Mapping
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Sequence Homology, Nucleic Acid
  • Viruses / enzymology
  • Viruses / genetics


  • Oligodeoxyribonucleotides
  • Recombinant Proteins
  • DNA-Directed DNA Polymerase

Associated data

  • GENBANK/M74198