Pleiotropic effect of the SCO2127 gene on the glucose uptake, glucose kinase activity and carbon catabolite repression in Streptomyces peucetius var. caesius

• Published in: Microbiology (Society for General Microbiology) 2005-05, Vol.151 (5), p.1717-1723
• Main Authors: Guzman, Silvia, Carmona, Alonso, Escalante, Laura, Imriskova, Iveta, Lopez, Ruth, Rodriguez-Sanoja, Romina, Ruiz, Beatriz, Servin-Gonzalez, Luis, Sanchez, Sergio, Langley, Elizabeth
• Format: Article
• Language: English
• Subjects: Antimetabolites - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Carbon - metabolism; Carbon - pharmacology; Culture Media; Deoxyglucose - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Glucokinase - genetics; Glucokinase - metabolism; Glucose - metabolism; Growth, nutrition, cell differenciation; Metabolism. Enzymes; Microbiology; Mutation; Recombination, Genetic; RNA, Bacterial - metabolism; Streptomyces - drug effects; Streptomyces - genetics; Streptomyces - metabolism; Transcription, Genetic
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.27557-0

Departamento de Biología Molecular y Biotecnología del Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, DF CP 04510, Mexico Correspondence Sergio Sánchez sersan{at}servidor.unam.mx SCO2127 and SCO2126 ( glkA ) are adjacent regions located in Streptomyces coelicolor DNA. glkA encodes glucose kinase (Glk), which has been implicated in carbon catabolite repression (CCR) in the genus Streptomyces . In this work, the glkA and SCO2127 genes from S. coelicolor were used, either individually or together, to transform three mutants of Streptomyces peucetius var. caesius resistant to CCR. These mutants present decreased levels of Glk, and deficiency in glucose transport. When the mutants were transformed with a plasmid containing the SCO2127 sequence, glucose uptake and Glk activity values were increased to levels similar to or higher than those of the original strain, and each strain regained sensitivity to CCR. This result was surprising considering that the putative SCO2127 amino acid sequence does not seem to encode a glucose permease or a Glk. In agreement with these results, an increase in glkA mRNA levels was observed in a CCR-resistant mutant transformed with SCO2127 compared with those of the original strain and the CCR-resistant mutant itself. As expected, recombinants containing the glkA sequence reverted Glk to normal activity values, but glucose uptake remained deficient. The data suggest that the SCO2127 gene product enhances transcription of both genes, and support the first specific role for this region in Streptomyces species. The physiological consequence of this effect is an increase in the glucose catabolites that may be involved in eliciting CCR in this genus. Abbreviations: CCR, carbon catabolite repression; 2-DOG, 2-deoxyglucose; Glk, glucose kinase; PEP, phosphoenolpyruvate; PTS, PEP-dependent sugar phosphotransferase system Present address: Department of Medical Genetics, 8-33 Medical Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2H7. Present address: Facultad de Medicina, Universidad Autónoma de Campeche, Campeche, Cam. 24090, Mexico.