Cloning and characterization of mouse deoxyguanosine kinase - Evidence fora cytoplasmic isoform

Citation
Tg. Petrakis et al., Cloning and characterization of mouse deoxyguanosine kinase - Evidence fora cytoplasmic isoform, J BIOL CHEM, 274(35), 1999, pp. 24726-24730
Citations number
30
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
00219258 → ACNP
Volume
274
Issue
35
Year of publication
1999
Pages
24726 - 24730
Database
ISI
SICI code
0021-9258(19990827)274:35<24726:CACOMD>2.0.ZU;2-6
Abstract
Deoxyguanosine kinase (dGK) is a nuclear gene product that catalyzes the ph osphorylation of purine deoxyribonucleosides and their analogues. The human enzyme is located predominantly in the mitochondria, as shown by biochemic al fractionation studies and in situ localization of the overexpressed reco mbinant protein. Here we describe the cloning of mouse dGK cDNA and the ide ntification of a novel amino-terminally truncated isoform that corresponds to about 14% of the total dGK mRNA population in mouse spleen. In situ fluo rescence assays suggest that the new isoform cannot translocate into the mi tochondria and thus may represent a cytoplasmic enzyme. Expression of mouse dGK mRNA was highly tissue-specific and differed from the tissue distribut ion observed in humans. Recombinant mouse dGK showed similar specific activ ity and substrate specificity as compared with the human enzyme. The broad specificity, restricted tissue distribution, and location of mouse dGK in m ultiple cellular compartments raise new considerations with respect to the role of the individual deoxynucleoside kinases in nucleotide metabolism.