Cloning and characterization of mouse deoxyguanosine kinase. Evidence for a cytoplasmic isoform

J Biol Chem. 1999 Aug 27;274(35):24726-30. doi: 10.1074/jbc.274.35.24726.

Abstract

Deoxyguanosine kinase (dGK) is a nuclear gene product that catalyzes the phosphorylation of purine deoxyribonucleosides and their analogues. The human enzyme is located predominantly in the mitochondria, as shown by biochemical fractionation studies and in situ localization of the overexpressed recombinant protein. Here we describe the cloning of mouse dGK cDNA and the identification of a novel amino-terminally truncated isoform that corresponds to about 14% of the total dGK mRNA population in mouse spleen. In situ fluorescence assays suggest that the new isoform cannot translocate into the mitochondria and thus may represent a cytoplasmic enzyme. Expression of mouse dGK mRNA was highly tissue-specific and differed from the tissue distribution observed in humans. Recombinant mouse dGK showed similar specific activity and substrate specificity as compared with the human enzyme. The broad specificity, restricted tissue distribution, and location of mouse dGK in multiple cellular compartments raise new considerations with respect to the role of the individual deoxynucleoside kinases in nucleotide metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • COS Cells
  • Cloning, Molecular
  • Isoenzymes / genetics
  • Mice
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Phosphotransferases (Alcohol Group Acceptor) / chemistry
  • Phosphotransferases (Alcohol Group Acceptor) / genetics*
  • RNA, Messenger / genetics
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Transfection

Substances

  • Isoenzymes
  • RNA, Messenger
  • Phosphotransferases (Alcohol Group Acceptor)
  • deoxyguanosine kinase

Associated data

  • GENBANK/AJ133749
  • GENBANK/AJ133750