title: The bldD gene of Streptomyces coelicolor A3(2): a regulatory gene involved in morphogenesis and antibiotic production.
abstract: The bld mutants of Streptomyces coelicolor A3(2) are blocked at the earliest stage of sporulation, the formation of aerial hyphae, and are pleiotropically defective in antibiotic production. Using a phage library of wild-type S. coelicolor DNA, we isolated a recombinant phage which restored both sporulation and antibiotic production to strains carrying the single known bldD mutation. Nucleotide sequence analysis of a 1.3-kb complementing subclone identified an open reading frame, designated bldD, encoding a translation product of 167 amino acid residues. Nucleotide sequence analysis of the bldD-containing fragment amplified from the chromosome of a bldD mutant strain revealed a point mutation changing a tyrosine residue at amino acid position 62 to a cysteine. Although a comparison of the BldD sequence to known proteins in the databases failed to show any strong similarities, analysis of the BldD sequence for secondary structural elements did reveal a putative helix-turn-helix, DNA recognition element near the C terminus of the protein. A comparison of bldD transcript levels in the bldD+ and bldD mutant strains using both Northern blot analysis and S1 nuclease protection studies showed vast overexpression of bldD transcripts in the mutant, suggesting that BldD negatively regulates its own synthesis. High-resolution S1 nuclease mapping identified the transcription start point as a G residue 63 nucleotides upstream from the bldD start codon and 7 nucleotides downstream from -10 and -35 sequences resembling E. coli-like streptomycete promoters.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Elliot
authors.forename: F
authors.initials: F
authors.lastname: Damji
authors.forename: R
authors.initials: R
authors.lastname: Passantino
authors.forename: K
authors.initials: K
authors.lastname: Chater
authors.forename: B
authors.initials: B
authors.lastname: Leskiw
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001435:Bacteriophages / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D018387:Codon, Initiator; D003545:Cysteine / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004268:DNA-Binding Proteins; D015870:Gene Expression; D015723:Gene Library; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D011995:Recombination, Genetic; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D013171:Spores, Bacterial / Q000235:genetics / Q000502:physiology; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D014157:Transcription Factors; D014158:Transcription, Genetic; D014443:Tyrosine / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C111306:BldD protein, Streptomyces coelicolor; D018387:Codon, Initiator; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012329:RNA, Bacterial; D014157:Transcription Factors; D014443:Tyrosine; D015719:Single-Strand Specific DNA and RNA Endonucleases; D003545:Cysteine