Rudimentary mutants ofDrosophila melanogaster
The X-linkedrudimentary (r) mutants ofDrosophila melanogaster are pyrimidine auxotrophs and require exogenous pyrimidines (Nørby, 1970; Falk, 1976). We have established a set ofrudimentary cell lines that are derived from embryos, homozygous for eitherr1 orr36. The enzymatic activities of the pyrimidine synthesizing enzymes were measured in the mutant lines. We have further investigated the nutritional requirements of the mutant cells in vitro by using a pyrimidine free culture medium.
Ther1 cell lines were found to express 3–7%dihydroorotase (DHOase) activity as compared to a wildtype cell line. Reducedaspartate transcarbamylase (ATCase) activity was measured in somer1 cell lines whereas wildtypecarbamylphosphate synthetase (CPSase) activity is expressed in allr1 cell lines. Ther36 cell line expresses wildtype activity ofDHOase andCPSase. ATCase activity was found to be reduced to 10% of the wildtype activity.
The mutant cell lines do not proliferate in pyrimidine free minimal medium and cell proliferation is obtained by the addition of crude RNA. Proliferation of ther1 cells is restored by the supplementation of the minimal medium withdihydroorotate whereas proliferation of ther36 cells is restored by supplementation with eitherdihydroorotate orcarbamylaspartate.
The results demonstrate that therudimentary phenotypesr1 andr36 are expressed at the cellular level and that the two mutant cell types behave as cellular pyrimidine auxotrophs in vitro.
Key wordsPyrimidine biosynthesis rudimentary mutants Drosophila melanogaster
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- Bernhard, H.P., Lienhard, S., Regenass, U.: Isolation and characterization of mutantDrosophila cell lines. In: Invertebrate tissue culture (E. Kurstak and K. Maramorosch, eds.) (in press, 1979)Google Scholar
- Carlson, P.S.: A genetic analysis of the rudimentary locus ofDrosophila melanogaster. Genet. Res.17, 53–81 (1971)Google Scholar
- Hartree, E.F.: Determination of protein: A modification of the Lowry method that gives a linear photometric response. Anal. Biochem.28, 422–427 (1972)Google Scholar
- Jones, M.E.: Regulation of uridylic acid biosynthesis in eucyryotic cells. In: Current topics in cellular regulation (B.L. Horecker and E.R. Stadtmann, eds.) New York: Academic Press, 1972Google Scholar
- Lindsley, D.L., Grell, E.H.: Genetic variations ofDrosophila melanogaster. Carnegie Inst. Washington Publ. No. 627 (1968)Google Scholar
- Makoff, A.G., Radford, A: Genetic and biochemistry of carbomyl phosphate biosynthesis and its utilization in the pyrimidine biosynthetic pathway. Microbiol. Rev. pp. 307–328 (1978)Google Scholar
- Mitsuhashi, J.: Insect cell line: amino acid utilization and requirements. In: Invertebrate tissue culture Applications in medicine, biology, and agriculture (E. Kurstak and K. Maramorosch, eds.) New York: Academic Press 1976Google Scholar
- Morgan, T.H.: A modification of the sex ratio and of other ratios inDrosophila through linkage. Z. Indukt. Abstamm. Vererbungsl.7, 323–345 (1912)Google Scholar
- Morgan, T.H.: The infertility of rudimentary winged females ofDrosophila ampelophila. Am. Nat.49, 240–250 (1915)Google Scholar
- Porter, W.R., Modebe, M.O., Stark, G.R.: Aspartate transcarbamylase, kinetic studies of the catalytic subunit. J. Biol. Chem.7, 1846–1859 (1969)Google Scholar
- Regenass, U.: Isolation of pole cells and auxotrophic cell lines fromDrosophila melanogaster maternal effect mutants. Basel: Ph. D. Thesis, University 1979Google Scholar
- Schneider, J., Blumenthal, A.B.:Drosophila cell and tissue culture. In: The genetics and biology ofDrosophila (M. Ashburner, T.R.F. Wright, eds.), Vol. 2a, pp. 265–315. New York: Academic Press 1978Google Scholar
- Shields, G., Dübendorfer, A., Sang, J.H.: Differentiation in vitro of larval cell types from early embryonic cells ofDrosophila melanogaster. J. Embryol. Expl. Morphol.33, 159–175 (1975)Google Scholar
- Shields, G., Sang, H.J.: Improved medium for culture ofDrosophila embryonic cells. Dros. Inf. Service52, 161 (1977)Google Scholar