Molecular cloning of tissue-specific transcripts of a transketolase-related gene: implications for the evolution of new vertebrate genes

Genomics. 1996 Mar 15;32(3):309-16. doi: 10.1006/geno.1996.0124.


As part of a systematic search for differentially expressed genes, we have isolated a novel transketolase-related gene (TKR) (HGMW-approved symbol TKT), located between the green color vision pigment gene (GCP) and the ABP-280 filamin gene (FLN1) in Xq28. Transcripts encoding tissue-specific protein isoforms could be isolated. Comparison with known transketolases (TK) demonstrated a TKR-specific deletion mutating one thiamine binding site. Genomic sequencing of the TKR gene revealed the presence of a pseudoexon as well as the acquisition of a tissue-specific spliced exon compared to TK. Since it has been postulated that the vertebrate genome arose by two cycles of tetraploidization from a cephalochordate genome, this could represent an example of the modulation of the function of a preexisting transketolase gene by gene duplication. Thiamine defiency is closely involved with two neurological disorders, Beriberi and Wernicke-Korsakoff syndromes, and in both of these conditions TK with altered activity are found. We discuss the possible involvement of TKR in explaining the observed variant transketolase forms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Binding Sites
  • Brain / embryology
  • Brain Chemistry
  • Chromosome Mapping
  • Cloning, Molecular
  • Evolution, Molecular
  • Exons / genetics
  • Fetal Heart / chemistry
  • Genes / genetics*
  • Humans
  • Molecular Sequence Data
  • Organ Specificity
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Deletion
  • Sequence Homology, Nucleic Acid
  • Thiamine
  • Transketolase / genetics*
  • Vertebrates / genetics*


  • RNA, Messenger
  • Transketolase
  • Thiamine

Associated data

  • GENBANK/X91817
  • GENBANK/X91818