Open AccessIntervening sequences in an Archaea DNA polymerase gene.
Author(s) -
Francine B. Perler,
Donald G. Comb,
William E. Jack,
Laurie S. Moran,
Boqin Qiang,
Rebecca Kucera,
Jack S. Benner,
Barton E. Slatko,
Donald O. Nwankwo,
S K Hempstead
Publication year - 1992
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.89.12.5577
Subject(s) - polymerase , exon , intron , biology , genetics , open reading frame , dna polymerase , microbiology and biotechnology , rna splicing , gene , peptide sequence , rna
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.