title: Isolation of Bacillus sphaericus biotin synthesis control mutants: evidence for transcriptional regulation of bio genes.
abstract: The genes involved in biotin synthesis have recently been isolated from Bacillus sphaericus [Gloeckler et al., Gene 87 (1990) 63-70]. Sequence analysis revealed that they are organized into two gene clusters, designated bioXWF and bioDAYB. The 5'-noncoding region of the bioD locus fused to the xylE reporter gene was inserted into the Gram-positive pUB110 replicon and the resulting plasmid was introduced into B. sphaericus IFO3525. Transformants expressed the xylE gene only if the biotin concentration in the growth medium remained below 50 ng/ml. After mutagenesis, colonies were screened for their ability to express the chromogenic marker in the presence of an excess of biotin. Most of these mutants escaped biotin repression of xylE gene expression. Classical genetic analysis showed they formed two main categories: chromosomal mutations, pleiotropically acting in trans on both bioXWF and bioDAYB 5'-noncoding regions, in which a 15-bp region common to both promoters represented a hot-spot for the second class of plasmid-associated mutations. These results, completed by the identification of transcription start points for the bioD and bioX genes, strongly suggest that this 15-bp sequence overlaps the site of a biotin-mediated negative regulation circuit controlling the transcription of the bio genes.
authors.affiliation: Transgène S.A., Strasbourg, France.
authors.forename: D
authors.initials: D
authors.lastname: Speck
authors.forename: I
authors.initials: I
authors.lastname: Ohsawa
authors.forename: R
authors.initials: R
authors.lastname: Gloeckler
authors.forename: M
authors.initials: M
authors.lastname: Zinsius
authors.forename: S
authors.initials: S
authors.lastname: Bernard
authors.forename: C
authors.initials: C
authors.lastname: Ledoux
authors.forename: T
authors.initials: T
authors.lastname: Kisou
authors.forename: K
authors.initials: K
authors.lastname: Kamogawa
authors.forename: Y
authors.initials: Y
authors.lastname: Lemoine
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000235:genetics*; D001483:Base Sequence; D001710:Biotin / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D050557:Catechol 2,3-Dioxygenase; D049308:Dioxygenases; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D011993:Recombinant Fusion Proteins; D001710:Biotin; D010105:Oxygenases; D049308:Dioxygenases; D050557:Catechol 2,3-Dioxygenase