Selective incorporation of thymidine in the organelle DNA of Polytoma obtusum.
Polytoma obtusum was found to selectively incorporate exogenous thymidine into its leukoplast DNA. The nuclear DNA was unable to incorporate [3H]thymidine, although both DNA species could be labeled with radioactive adenine with similar efficiencies. The mitochondrial DNA (mitDNA), which had a buoyant density of 1.714 g/ml and was banded slightly on the heavier side of the nuclear DNA peak, was also found to incorporate a small amount of [3H]thymidine. These observations suggest that P. obtusum lack cytoplasmic thymidine kinase, whereas the enzyme is present in both leukoplast and mitochondria.
D000225:Adenine / Q000378:metabolism; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis*; D004272:DNA, Mitochondrial / Q000096:biosynthesis; D056890:Eukaryota / Q000378:metabolism* / Q000648:ultrastructure; D008928:Mitochondria / Q000201:enzymology; D009940:Organoids / Q000201:enzymology / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism*; D013937:Thymidine Kinase / Q000378:metabolism
D004272:DNA, Mitochondrial; D004247:DNA; D013937:Thymidine Kinase; D000225:Adenine; D013936:Thymidine