RESUMEN
Transcriptional factors of the GntR family regulate numerous physiological and morphological processes in response to the nutrient state of bacterial cells. The number of GntR transcriptional factors in genomes of soil-dwelling actinomycetes is one of the highest among bacteria, reflecting both the large size of their chromosomes and the complex ecological niche that they occupy. However, very little is known about the roles of GntRs in actinomycete biology. Here, we analyzed the genome of model actinomycete, Streptomyces coelicolor A3(2), in an attempt to gain new insights into the function of GntR family. All 56 GntR proteins of M145 strain were classified into FadR, HutC, MocR, YtrA, and DevA subfamilies according to their secondary structure. We then checked for the presence of GntR orthologs in six other sequenced Streptomyces and one Kitasatospora genomes, revealing that 12 GntRs were conserved in all analyzed strains. Genomic analysis of the less studied YtrA type regulators revealed 160 sequences present in 88 members of Coriobacteridae, Rubrobacteridae, and Actinobacteridae subclasses. These proteins form seven dense clusters on the consensus phylogenetic tree and their genes are usually co-located with the genes for transport proteins. Probable operator sites were identified for orthologous groups of Sco0823 and Sco3812 proteins. All S. coelicolor YtrA-like regulatory genes (SCO0823, SCO1728, SCO3812) were analyzed at transcriptional level, knocked out, and introduced on moderate copy number plasmid in M145 strain. Also, gene SCO0824, a part of putative SCO0823 operon, was studied. Results of these experiments are discussed here.
Asunto(s)
Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Familia de Multigenes , Streptomyces coelicolor/genética , Streptomyces coelicolor/metabolismo , Factores de Transcripción/metabolismo , Transcripción Genética , Antibacterianos/biosíntesis , Biología Computacional/métodos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Bases de Datos Genéticas , Técnicas de Inactivación de Genes , Genoma Bacteriano , Glucuronidasa/metabolismo , Sistemas de Lectura Abierta , Fenotipo , Filogenia , Streptomyces coelicolor/clasificaciónRESUMEN
Moenomycins (Mm) - phosphoglycolipid compounds produced by Streptomyces ghanaensis ATCC14672 - are considered a promising model for development of novel class of antibiotics. In this regard it is important to generate Mm overproducing strains which would be a basis for economically justified production of this antibiotic. In this work a set of genes for synthesis and reception of low-molecular weight signaling molecules (LSM) in ATCC14672 were described and their significance for Mm production was studied. The ATCC14672 genome carries structural and regulatory genes for production of LSMs of avenolide and γ-butyrolactone families. Additional copies of LSM biosynthetic genes ssfg_07848 and ssfg_07725 did not alter the Mm production level. ATCC14672 LSMs are not capable of restoring the sporulation of butyrolactone-nonproducing mutant of S. griseus. Likewise, while the heterologous host S. lividans 1326 produced Mm, its mutant M707 (deficient in the butyrolactone synthase gene scbA) did not. Thus, while the natural level of LSMs production by ATCC14672 does not limit Mm synthesis, the former is essential for the synthesis of moenomycins.
RESUMEN
Moenomycins (Mm)--phosphoglycolipid compounds produced by Streptomyces ghanaensis ATCC14672--are considered a promising model for development of novel-class of antibiotics. In this regard it is important to generate Mm overproducing strains which would be a basis for economically justified production of this antibiotic. In this work a set of genes for synthesis and reception of low-molecularweight signaling molecules (LSM) in ATCC14672 were described and their significance for Mm production was studied. The ATCC 14672 genome carries structural and regulatory genes for production of LSMs of avenolide and γ-butyrolacone families. Additional copies of LSM biosynthetic genes ssfg_07848 and ssfg_07725 did not alter the Mm production level. ATCC14672 LSMs are not capable of restoring the sporulation of butyrolactone-nonpro-ucing mutant ofS . griseus. Likewise, while the heterologous host S. lividans 1326 produced Mm, its mutant M707 (deficient in the butyrolactone synthase gene scbA) did not. Thus, while the natural level of LSMs pro-uction by ATCC 14672 does not limit Mm synthesis, the former is essential for the synthesis of moenomycins.
Asunto(s)
4-Butirolactona/análogos & derivados , Genes Bacterianos , Oligosacáridos/biosíntesis , Streptomyces/genética , 4-Butirolactona/biosíntesis , 4-Butirolactona/genética , Mutación , Oligosacáridos/genética , Transducción de Señal/genética , Streptomyces/metabolismoRESUMEN
Streptomyces globisporus 1912 lnd-cluster region which flanks structural lndZ5-lndZ6 genes contains four open reading frames lndW, lndW2, lndYR and lndY. The latter one encodes putative proteinase which can regulate landomycin production and morphogenesis like LndYR. However, results of lndY overexpression and gene knockout showed that lndY did not participate in regulation of landomycin production and morphogenesis of Streptomyces globisporus 1912. Using transcriptional fusion of promoter lndWp to catechol dioxygenase reporter gene xylE the temporal character of interaction of promoter lndWp and repressor LndYR was studied.