title: Investigations on the organization of genetic loci in Drosophila melanogaster: lethal mutations affecting 6-phosphogluconate dehydrogenase and their suppression.
abstract: The molecular nature of lethal and semilethal mutations in the Pgd locus of D. melanogaster coding for 6-phosphogluconate dehydrogenase (6PGD) was studied. All the 11 mutations affect the structural gene of the Pgd locus: 3 semilethal mutations resulted in altered 6PGD molecules with decreased catalytic activities; the rest 8 lethals were "null" alleles characterized by mutant polypeptides capable of reacting with antisera against highly purified 6PGD. "Null" or low activity alleles for glucose-6-phosphate dehydrogenase induced by ethyl methanesulfonate were shown to be suppressores for the lethal mutations in the Pgd locus. A monocistronic type of organization of the Pgd locus is suggested taking into account the biochemical mechanism of suppression of the Pgd-lethals and their location in the structural gene coding for 6PGD.
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000648:ultrastructure*; D005260:Female; D005796:Genes; D005804:Genes, Lethal; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D008297:Male; D009154:Mutation; D010734:Phosphogluconate Dehydrogenase / Q000378:metabolism*; D013489:Suppression, Genetic
chemical_list: D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase