Studies on the female sterile mutantRudimentary ofDrosophila melanogaster. IV. The activities of de novo and salvage pathway enzymes for pyrimidine biosynthesis during oogenesis, embryonic and postembryonic development of wild-type flies
✍ Scribed by Fausto-Sterling, Anne
- Publisher
- John Wiley and Sons
- Year
- 1981
- Tongue
- English
- Weight
- 575 KB
- Volume
- 218
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
In order to gain a better understanding of how a defect in pyrimidine biosynthesis leads to the specific set of morphological aberrations seen in Drosophila bearing the mutant allele of rudimentary, we made the following measurements of enzyme activity in wild type flies: (1) during ovarian development – the first three enzymes of the de novo pathway for pyrimidine biosynthesis (aspartate transcarbamylase, dihydroorotase, and carbamyl phosphate synthetase) and two enzymes in the salvage pathway for pyrimidine biosynthesis – uridine kinase and uridine phosphorylase; (2) during embryonic development – uridine kinase and uridine phosphorylase in embryos taken at hourly intervals; and (3) during postembryonic development – uridine kinase and uridine phosphorylase.
Our results suggest: (1) that the de novo pyrimidine enzymes are synthesized during the early stages of oogenesis, while the pattern for the salvage pathway enzymes is somewhat different; (2) that a lowering of uridine kinase activity at 13 hours of embryonic development may be responsible for bringing on the developmental crisis in r embryos; and (3) that the postembryonic pattern of activity for salvage pathway enzymes, with one exception, is quite similar to that for the de novo pathway enzymes.