Identification of Three New Genes Involved in Morphogenesis and Antibiotic Production in Streptomyces coelicolor

We report the isolation and partial characterization of three new mutants of Streptomyces coelicolor that are defective in morphogenesis and antibiotic production. The genes identified by the mutations were located and cloned by using a combination of Tn5 in vitro mutagenesis, cotransformation, and genetic complementation. Mutant SE69 produces lower amounts of antibiotics than the wild type produces, produces spores only after prolonged incubation on rich media, and identifies a gene whose predicted protein product is similar to the GntR family of transcriptional regulators; also, production of aerial mycelia on both rich and poor media is significantly delayed in this mutant. Mutant SE293 is defective in morphogenesis, overproduces antibiotics on rich media, fails to grow on minimal media, and identifies a gene whose predicted protein product is similar to the TetR family of transcriptional regulators. Preliminary evidence suggests that the SE293 gene product may control a molybdopterin binding protein located immediately adjacent to it. Mutant SJ175 sporulates sooner and more abundantly than the wild type and overproduces antibiotics on rich media, and it identifies a gene whose predicted protein product contains regions of predominantly hydrophobic residues similar to those of integral membrane proteins

The bkdR Gene of Streptomyces coelicolor Is Required for Morphogenesis and Antibiotic Production and Encodes a Transcriptional Regulator of a Branched-Chain Amino Acid Dehydrogenase Complex

Products from the degradation of the branched-chain amino acids valine, leucine, and isoleucine contribute to the production of a number of important cellular metabolites, including branched-chain fatty acids, ATP and other energy production, cell-cell signaling for morphological development, and the synthesis of precursors for polyketide antibiotics. The first nonreversible reactions in the degradation of all three amino acids are catalyzed by the same branched-chain α-keto acid dehydrogenase (BCDH) complex. Actinomycetes are apparently unique among bacteria in that they contain two separate gene clusters, each of which encodes a BCDH enzyme complex. Here, we show that one of these clusters in Streptomyces coelicolor is regulated, at least in part, at the level of transcription by the product of the bkdR gene. The predicted product of this gene is a protein with similarity to a family of proteins that respond to leucine and serve to activate transcription of amino acid utilization operons. Unlike most other members of this class, however, the S. coelicolor bkdR gene product serves to repress transcription, suggesting that the branched-chain amino acids act as inducers rather than coactivators of transcription. BkdR likely responds to the presence of branched-chain amino acids. Its role in transcriptional regulation may be rationalized by the fact that transition from vegetative growth to aerial mycelium production, the first stage of morphological development in these complex bacteria, is coincident with extensive cellular lysis generating abundant amounts of protein that likely serve as the predominant source of carbon and nitrogen for metabolism. We suggest that bkdR plays a key role in the ability of Streptomyces species to sense nutrient availability and redirect metabolism for the utilization of branched-chain amino acids for energy, carbon, and perhaps even morphogen synthesis. A null mutant of bkdR is itself defective in morphogenesis and antibiotic production, suggesting that the role of the bkdR gene product may be more global than specific nutrient utilization

Student Recital (December 4, 2009)

Fairy-tale Pictures, Op. 113 / Robert Schumann 1. Nicht Schnell Sue Blazejewski, viola In the Silence of Night, Op. 4, No. 3 / Sergei Rachmaninoff I Could Have Danced All Night / Frederick Loewe Jordan Ennis, Voice Sonata No. 3 / George Frederick Handel 1. Allegro Sean Every, Alto Saxophone Sonata IV / Johann Sebastian Bach Elizabeth Ferrisi, Flute Andante Cantabile / Marco Bordogni Andrew Shaw, Euphonium English Suite No. 2, BWV 807 / J. S. Bach Courante Sarabande Kurumi Ueno, Piano “Non so piu cosa son” from Le Nozze Di Figaro / Wolfgang Amadeus Mozart Meghan Foley, mezzo soprano I Attempt from Love’s Sickness / Henry Purcell My Lovely Celia / George Monro Chelsea Dubin, Soprano The Silver Aria / Douglas Moore Jen Martin, Soprano The Lass from the Low Countree / John Jacob Niles Katie Sprusansky, mezzo soprano Er, der Herrlichste von Allen / R. Schumann Nuit d’Etoiles – Claude Debussy (1862-1918) Amy Cromer, Soprano Vittoria Mio Core! / Giacomo Carissimi Stuart Cabral, Countertenor Revenge, Timotheus cries / G. F. Handel Patrick McMahon, Bass En Sourdine / Gabriel Faure What Can We Poor Females Do / H. Purcell Amanda Goff, mezzo soprano Gretchen am Spinnrade / Franz Schubert Va Godendo / G. F. Handel Nicole DeGennaro, soprano An die Nachtigall, Op. 46, No. 4 / Johannes Brahms St. Ita’s Vision, Op. 29, No. 3 / Samuel Barber Teresa Carr, soprano Dichterliebe, Op. 48 / R. Schumann XIII. Ich hab’ im Traum geweinet XIV. Allnachtlich im Traume Cameron Estrella, Baritonehttps://vc.bridgew.edu/student_concerts/1012/thumbnail.jp

Student Recital (April 15, 2011)

Two, As One, In Three / John LaPorta Interplay / J. LaPorta Daniel Hatchfield, trombone Andrew Shaw, euphonium Suite No. 3 in C / Johann Sebastian Bach 1. Prelude Susan Blazejewski, viola Piano Sonata No. 2, Op. 31 / Dianne Goolkasian Rahbee) 1. Allegro maestoso Kurumi Ueno, piano Dank sei Dir, Herr / Georg Friedrich Handel If you’ve only got a moustache / Stephen Collins Foster Patrick McMahon, bass Sonata for Flute / Paul Hindemith II. Sehr langsam Deidre Balunas, flute Black is the Color of My True Love’s Hair / John Jacob Niles Noh-Kyung Park, soprano Two Hues of Blue / Lenny Niehaus 1. Moderate Blues Sean Every, alto saxophone Pieta, Signore / Alessandro Stradella Ave Maria / C. Gounod Joseph Steinkrauss, baritone El Testamen de N’amelia / Miguel Llobet Ian Timpany, guitar Vanilla Ice Cream / Jerry Bock Alison Kenney, soprano Lied der Mignon, Op. 62 / Franz Schubert Katie Sprusansky, mezzo soprano Oboe Concerto in C minor / Benedetto Marcello III. Allegro James-ace Thackston, soprano saxophone Trio in C Major for Two Violins and Viola, Op. 87 / Ludwig Van Beethoven 1. Allegro Chelsea White, violin I Elizabeth Smith, violin II Carla Mason, violin III Gail Columbo, violin IV Susan Blazejewski, violahttps://vc.bridgew.edu/student_concerts/1008/thumbnail.jp

Variation in form and function: the helix-turn-helix regulators of the GntR superfamily

One of the most abundant and widely distributed groups of Helix-turn-helix (HTH) transcription factors is the metabolite-responsive GntR family of regulators (>8500 members in the Pfam database; Jan 2009). These proteins contain a DNA-binding HTH domain at the N terminus of the protein and an effector-binding and/or oligomerisation domain at the C terminus, where upon on binding an effector molecule, a conformational change occurs in the protein which influences the DNA-binding properties of the regulator resulting in repression or activation of transcription. This review summarises what we know about the distribution, structure, function and classification of these regulators and suggests that they may have a future role in biotechnology