title: Attempts to isolate mutants of Dictyostelium discoideum which express alpha-mannosidase-2 constitutively.
abstract: Evidence was sought for a gene-specific negative regulatory element of Dictyostelium discoideum similar to the repressor/operator systems that control some operons in prokaryotes and their viruses. Mutants of D. discoideum that constitutively express the stage-specific enzyme alpha-mannosidase-2 could provide such evidence. Reconstruction experiments demonstrated that the screening technique developed would detect mutants of that type. Over 2 x 10(5) survivors of heavily mutagenized cell populations were grown and their progeny tested. No mutants of the desired type were obtained. The possible implications of this finding are discussed.
mesh_terms: D004023:Dictyostelium / Q000201:enzymology / Q000235:genetics*; D005809:Genes, Regulator; D008361:Mannosidases / Q000378:metabolism*; D009154:Mutation; D009876:Operon
chemical_list: D008361:Mannosidases