salicylates and Chromosome-Deletion

The biphenyl and salicylate metabolic pathways in Pseudomonas putida KF715 are chromosomally encoded. The bph gene cluster coding for the conversion of biphenyl to benzoic acid and the sal gene cluster coding for the salicylate meta-pathway were obtained from the KF715 genomic cosmid libraries. These two gene clusters were separated by 10-kb DNA and were highly prone to deletion when KF715 was grown in nutrient medium. Two types of deletions took place at the region including only the bph genes (ca. 40 kb) or at the region including both the bph and sal genes (ca. 70 kb). A 90-kb DNA region, including both the bph and sal genes (termed the bph-sal element), was transferred by conjugation from KF715 to P. putida AC30. Such transconjugants gained the ability to grow on biphenyl and salicylate as the sole sources of carbon. The bph and sal element was located on the chromosome of the recipient. The bph-sal element in strain AC30 was also highly prone to deletion; however, it could be mobilized to the chromosome of P. putida KT2440 and the two deletion mutants of KF715.

Topics: Base Sequence; Benzoic Acid; Biphenyl Compounds; Blotting, Southern; Chromosome Deletion; Chromosomes, Bacterial; Conjugation, Genetic; Electrophoresis, Gel, Pulsed-Field; Genes, Bacterial; Genetic Complementation Test; Molecular Weight; Multigene Family; Mutation; Phenotype; Pseudomonas putida; Recombination, Genetic; Restriction Mapping; Salicylates

The cis-acting elements for regulating gene expression of the tobacco pathogenesis-related 1a protein gene were analyzed in transgenic plants. The 5'-flanking 2.4-kilobase fragment from the pathogenesis-related 1a protein gene was joined to the bacterial beta-glucuronidase gene and introduced into tobacco cells by Agrobacterium-mediated gene transfer. Promoter activity was monitored by quantitative and histochemical assay of beta-glucuronidase activity in leaves of regenerated transgenic plants. The level of beta-glucuronidase activity was clearly increased by treatment with salicylic acid, by cutting stress, and by local lesion formation caused by tobacco mosaic virus infection. Cytochemical studies of the induced beta-glucuronidase activity revealed tissue-specific and developmentally regulated expression of the pathogenesis-related 1a gene after stress or chemical treatment and after pathogen attack. To identify the cis-acting element more precisely, a series of 5'-deleted chimeric genes was constructed and transformed into tobacco plants. Transgenic plants with a 0.3-kilobase fragment of the 5'-flanking region of the pathogenesis-related 1a gene had the same qualitative response as those with the 2.4-kilobase fragment upon treatment with salicylic acid or infection with TMV. Thus, the 0.3-kilobase DNA sequence fragment was sufficient to allow the regulated expression of the pathogenesis-related 1a gene.

Topics: Base Sequence; Chromosome Deletion; Enzyme Induction; Gene Expression Regulation; Genetic Vectors; Glucuronidase; Histocytochemistry; Kanamycin Resistance; Molecular Sequence Data; Nicotiana; Plant Proteins; Plants, Genetically Modified; Plants, Toxic; Regulatory Sequences, Nucleic Acid; Salicylates; Salicylic Acid

The product of the nahR gene, a salicylate-dependent activator of transcription of the nah and sal hydrocarbon degradation operons of the NAH7 plasmid, was identified and characterized after synthesis in Escherichia coli maxicells. The nahR gene product had a subunit molecular weight of 36,000, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas gel filtration analysis of the nondenatured nahR protein indicated a molecular weight in excess of 250,000. However, DNase I treatment of this high-molecular-weight complex shifted the apparent molecular weight of the nahR protein to 40,000. Various upstream portions of the sal operon promoter were transcriptionally fused to the E. coli galactokinase gene. Fusion plasmids containing the sal promoter sequence from --83 to 27 (relative to the transcription start site) showed salicylate-inducible expression of galactokinase in the presence of the cloned nahR gene, while expression of galactokinase from a fusion plasmid containing the sal promoter sequence from --45 to 27 was not induced by the nahR gene and salicylate. Results suggest that the nahR gene product is a 36-kilodalton polypeptide which exerts its salicylate-dependent activation of transcription of the sal operon by interacting with the promoter sequence in the region of --83 to --45 base pairs before the transcription start site.

Topics: Bacterial Proteins; Base Sequence; Chromatography, Gel; Chromosome Deletion; Cloning, Molecular; DNA, Bacterial; Genes, Bacterial; Genes, Regulator; Naphthalenes; Operon; Promoter Regions, Genetic; Salicylates; Salicylic Acid; Transcription, Genetic

Steroid sulfatase (STS)-deficient X-linked ichthyosis was diagnosed in a man with short stature and mental retardation. His generation includes five similarly affected male members. A translocation chromosome is segregating in this Newfoundland kindred. The proband's mother and grandmother have normal skin and are of normal intelligence. From his carrier mother, the proband inherited an X short arm (Xp) to Y long arm (Yq) translocation chromosome, with the entire Y short arm and the X short arm terminal segment deleted (Xp223-pter). His cells are completely deficient in STS activity, confirming assignment of the STS locus to Xp223-pter. Effective management of his ichthyosis included treatment with 6% salicylic acid gel under plastic occlusion and removal of the scales by scrubbing.

Topics: Adult; Child; Chromosome Aberrations; Chromosome Deletion; Female; Gels; Genetic Linkage; Humans; Ichthyosis; Intellectual Disability; Male; Pedigree; Salicylates; Salicylic Acid; Skin; Steryl-Sulfatase; Sulfatases; Translocation, Genetic; X Chromosome