Control of Drosophila deoxyuridine triphosphatase. Existence of a developmentally expressed protein inhibitor

An activity that inhibits deoxyuridine triphosphatase (dUTPase) has been partially purified from Drosophila melanogaster. The inhibitor has a sedimentation coefficient of 4.1 S and a subunit molecular mass of 61 kDa. Its expression is limited to early stages of development, similar to the pattern previously found for dUTPase. The inhibitor is unusually stable to heating and is insensitive to DNAse and RNAse treatment. On the other hand, inhibition is sensitive to digestion with proteinase K, indicating that a protein is required for activity. These results suggest that at least one form of regulation is exerted on Drosophila dUTPase that could allow a greater opportunity for the incorporation of uracil into DNA.