title: Regulation of fatty acid degradation in Escherichia coli: dominance studies with strains merodiploid in gene fadR.
abstract: Strains stably merodiploid in the 25-min region of the chromosome of Escherichia coli were constructed and used in dominance tests between various wild-type and mutant alleles of the fadR gene. Whereas the monoploid fadR+ and fadR strains were inducible and constitutive, respectively, for the enzymes involved in fatty acid degradation (fad), merodiploids with at least one fadR+ allele were inducible. This observation was true whether the fadR+ allele resided on the main chromosome or on the episome. These results show that fadR+ is trans dominant to fadR, and they are consistent with the proposal that the fadR gene product is a repressor protein. Complementation tests were also performed by constructing 24 merodiploids harboring fadR alleles on both the main chromosome and the episome. All of these fadR/fadR diploids were able to utilize the noninducing substrate decanoate as sole carbon source, suggesting that only one polypeptide is encoded by the fadR gene.
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D005796:Genes; D005799:Genes, Dominant; D005816:Genetic Complementation Test; D010084:Oxidation-Reduction; D012097:Repressor Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D005227:Fatty Acids; D012097:Repressor Proteins; D014157:Transcription Factors