This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Gonzalez-y-Merchand, J. A.
Right arrow Articles by Cox, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Gonzalez-y-Merchand, J. A.
Right arrow Articles by Cox, R. A.

 Previous Article  |  Next Article 

Journal of Bacteriology, August 1999, p. 4617-4627, Vol. 181, No. 15
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Effects of Growth Conditions on Expression of Mycobacterial murA and tyrS Genes and Contributions of Their Transcripts to Precursor rRNA Synthesis

J. A. Gonzalez-y-Merchand,1 M. J. Colston,2 and R. A. Cox2,*

Departamento de Microbiologia, Escuela Nacional de Ciencias Biologicas, IPN, Mexico, Distrito Federal 06400, Mexico,1 and Division of Mycobacterial Research, National Institute for Medical Research, London NW7 1AA, United Kingdom2

Received 29 January 1999/Accepted 21 May 1999

All mycobacteria studied to date have an rRNA operon, designated rrnA, located downstream from a single copy of the murA gene, which encodes an enzyme (EC 2.5.1.7) important for peptidoglycan synthesis. The rrnA operon has a promoter, P1(A), located within the coding region of murA, near the 3' end. Samples of RNA were isolated from Mycobacterium tuberculosis at different stages of the growth cycle and from Mycobacterium smegmatis grown under different conditions. RNase protection assays were used to investigate transcripts of both murA and rrnA. Transcription of murA was found to continue into the 16S rRNA gene, as if murA and rrnA form a hybrid (protein coding-rRNA coding) operon. During the growth of M. tuberculosis, the hybrid operon contributed approximately 2% to total pre-rRNA. Analysis of M. smegmatis RNA revealed that the level of murA RNA depended on the growth rate and that the patterns of expression during the growth cycle were different for murA and rrnA. M. smegmatis has a second rRNA operon, rrnB, located downstream from a single copy of the tyrS gene, encoding tyrosyl-tRNA synthetase. Transcription of tyrS was found to continue into the 16S rRNA gene rrnB. The hybrid tyrS-rrnB operon contributed 0.2 to 0.6% to rrnB transcripts. The pattern of tyrS expression during the growth cycle matched the pattern of rrnB expression, reflecting the essential role of TyrS and rRNA in protein biosynthesis.

* Corresponding author. Mailing address: Division of Mycobacterial Research, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom. Phone: 44 181 959 3666. Fax: 44 181 906 4477. E-mail: rcox{at}nimr.mrc.ac.uk.

Journal of Bacteriology, August 1999, p. 4617-4627, Vol. 181, No. 15
0021-9193/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.


This article has been cited by other articles:

  • Arnvig, K. B., Gopal, B., Papavinasasundaram, K. G., Cox, R. A., Colston, M. J. (2005). The mechanism of upstream activation in the rrnB operon of Mycobacterium smegmatis is different from the Escherichia coli paradigm. Microbiology 151: 467-473 [Abstract] [Full Text]  
  • Cox, R. A. (2004). Quantitative relationships for specific growth rates and macromolecular compositions of Mycobacterium tuberculosis, Streptomyces coelicolor A3(2) and Escherichia coli B/r: an integrative theoretical approach. Microbiology 150: 1413-1426 [Abstract] [Full Text]  
  • Kumar, A., Bose, M., Brahmachari, V. (2003). Analysis of Expression Profile of Mammalian Cell Entry (mce) Operons of Mycobacterium tuberculosis. Infect. Immun. 71: 6083-6087 [Abstract] [Full Text]  
  • Cox, R. A. (2003). Correlation of the rate of protein synthesis and the third power of the RNA : protein ratio in Escherichia coli and Mycobacterium tuberculosis. Microbiology 149: 729-737 [Abstract] [Full Text]  
  • Menendez, M. C., Garcia, M. J., Navarro, M. C., Gonzalez-y-Merchand, J. A., Rivera-Gutierrez, S., Garcia-Sanchez, L., Cox, R. A. (2002). Characterization of an rRNA Operon (rrnB) of Mycobacterium fortuitum and Other Mycobacterial Species: Implications for the Classification of Mycobacteria. J. Bacteriol. 184: 1078-1088 [Abstract] [Full Text]  
  • Harris, N. B., Barletta, R. G. (2001). Mycobacterium avium subsp. paratuberculosis in Veterinary Medicine. Clin. Microbiol. Rev. 14: 489-512 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»