J. Bacteriol., 04 1996, 1800-1808, Vol 178, No. 7
Copyright © 1996, American Society for Microbiology

Characterization of the genes coding for the putative sigma factor AlgU and its regulators MucA, MucB, MucC, and MucD in Azotobacter vinelandii and evaluation of their roles in alginate biosynthesis

JM Martinez-Salazar, S Moreno, R Najera, JC Boucher, G Espin, G Soberon-Chavez and V Deretic
Departamento de Microbiologia Molecular, Instituto de Biotecnologia, Universidad Nacional Autonoma de Mexico, Morelos, Mexico.

The study of the biosynthesis of alginate, the exopolysaccharide produced by Azotobacter vinelandii and Pseudomonas aeruginosa, has biotechnological and medical significance. We report here the identification of the A. vinelandii genes coding for the putative sigma factor AlgU and its negative regulators MucA and MucB through the suppression of the highly mucoid phenotype of an A. vinelandii strain by a plasmid encoding MucA and MucB. The sequences of the A. vinelandii algU, mucA, and mucB genes are highly homologous to those of the corresponding P. aeruginosa genes, AlgU shows 93% identity, and MucA and MucB are 64.4 and 63.9% identical, respectively. Forming part of the same operon as algU, mucA, and mucB, two additional genes (mucC and mucD) were identified and sequenced; the product of the former gene is homologous to ORF4 of Photobacterium sp. strain SS9, and that of the latter gene belongs to the HtrA serine protease family. Interestingly, the nonmucoid A. vinelandii UW136 had a 0.9-kb insertion within the algU gene. A strong correlation between AlgU activity and alginate production by A. vinelandii was also found, as reflected in the level of algD transcription.

This article has been cited by other articles:

• Flannagan, R. S., Valvano, M. A. (2008). Burkholderia cenocepacia requires RpoE for growth under stress conditions and delay of phagolysosomal fusion in macrophages. Microbiology 154: 643-653 [Abstract] [Full Text]  
• Schenk, A., Berger, M., Keith, L. M., Bender, C. L., Muskhelishvili, G., Ullrich, M. S. (2006). The algT Gene of Pseudomonas syringae pv. glycinea and New Insights into the Transcriptional Organization of the algT-muc Gene Cluster. J. Bacteriol. 188: 8013-8021 [Abstract] [Full Text]  
• Gimmestad, M., Steigedal, M., Ertesvag, H., Moreno, S., Christensen, B. E., Espin, G., Valla, S. (2006). Identification and Characterization of an Azotobacter vinelandii Type I Secretion System Responsible for Export of the AlgE-Type Mannuronan C-5-Epimerases.. J. Bacteriol. 188: 5551-5560 [Abstract] [Full Text]  
• Kaufusi, P. H., Forsberg, L. S., Tittabutr, P., Borthakur, D. (2004). Regulation of exopolysaccharide synthesis in Rhizobium sp. strain TAL1145 involves an alternative sigma factor gene, rpoH2. Microbiology 150: 3473-3482 [Abstract] [Full Text]  
• Lizewski, S. E., Schurr, J. R., Jackson, D. W., Frisk, A., Carterson, A. J., Schurr, M. J. (2004). Identification of AlgR-Regulated Genes in Pseudomonas aeruginosa by Use of Microarray Analysis. J. Bacteriol. 186: 5672-5684 [Abstract] [Full Text]  
• Leverrier, P., Dimova, D., Pichereau, V., Auffray, Y., Boyaval, P., Jan, G. (2003). Susceptibility and Adaptive Response to Bile Salts in Propionibacterium freudenreichii: Physiological and Proteomic Analysis. Appl. Environ. Microbiol. 69: 3809-3818 [Abstract] [Full Text]  
• Schnider-Keel, U., Lejbolle, K. B., Baehler, E., Haas, D., Keel, C. (2001). The Sigma Factor AlgU (AlgT) Controls Exopolysaccharide Production and Tolerance towards Desiccation and Osmotic Stress in the Biocontrol Agent Pseudomonas fluorescens CHA0. Appl. Environ. Microbiol. 67: 5683-5693 [Abstract] [Full Text]  
• Castaneda, M., Sanchez, J., Moreno, S., Nunez, C., Espin, G. (2001). The Global Regulators GacA and sigma S Form Part of a Cascade That Controls Alginate Production in Azotobacter vinelandii. J. Bacteriol. 183: 6787-6793 [Abstract] [Full Text]  
• Page, W. J., Tindale, A., Chandra, M., Kwon, E. (2001). Alginate formation in Azotobacter vinelandii UWD during stationary phase and the turnover of poly-{beta}-hydroxybutyrate. Microbiology 147: 483-490 [Abstract] [Full Text]  
• Núñez, C., León, R., Guzmán, J., Espín, G., Soberón-Chávez, G. (2000). Role of Azotobacter vinelandii mucA and mucC Gene Products in Alginate Production. J. Bacteriol. 182: 6550-6556 [Abstract] [Full Text]  
• Ullrich, M. S., Schergaut, M., Boch, J., Ullrich, B. (2000). Temperature-responsive genetic loci in the plant pathogen Pseudomonas syringae pv. glycinea. Microbiology 146: 2457-2468 [Abstract] [Full Text]  
• Núñez, C., Moreno, S., Cárdenas, L., Soberón-Chávez, G., Espín, G. (2000). Inactivation of the ampDE Operon Increases Transcription of algD and Affects Morphology and Encystment of Azotobacter vinelandii. J. Bacteriol. 182: 4829-4835 [Abstract] [Full Text]  
• Castañeda, M., Guzmán, J., Moreno, S., Espín, G. (2000). The GacS Sensor Kinase Regulates Alginate and Poly-beta -Hydroxybutyrate Production in Azotobacter vinelandii. J. Bacteriol. 182: 2624-2628 [Abstract] [Full Text]  
• Keith, L. M. W., Bender, C. L. (1999). AlgT (sigma 22) Controls Alginate Production and Tolerance to Environmental Stress in Pseudomonas syringae. J. Bacteriol. 181: 7176-7184 [Abstract] [Full Text]  
• Ades, S. E., Connolly, L. E., Alba, B. M., Gross, C. A. (1999). The Escherichia coli sigma E-dependent extracytoplasmic stress response is controlled by the regulated proteolysis of an anti-sigma factor. Genes Dev. 13: 2449-2461 [Abstract] [Full Text]  
• Núñez, C., Moreno, S., Soberón-Chávez, G., Espín, G. (1999). The Azotobacter vinelandii Response Regulator AlgR Is Essential for Cyst Formation. J. Bacteriol. 181: 141-148 [Abstract] [Full Text]  
• Segura, D., Espín, G. (1998). Mutational Inactivation of a Gene Homologous to Escherichia coli ptsP Affects Poly-beta -Hydroxybutyrate Accumulation and Nitrogen Fixation in Azotobacter vinelandii. J. Bacteriol. 180: 4790-4798 [Abstract] [Full Text]  
• Moreno, S., Nájera, R., Guzmán, J., Soberón-Chávez, G., Espín, G. (1998). Role of Alternative sigma  Factor AlgU in Encystment of Azotobacter vinelandii. J. Bacteriol. 180: 2766-2769 [Abstract] [Full Text]