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

Regulation of Transcription in a Reduced Bacterial Genome: Nutrient-Provisioning Genes of the Obligate Symbiont Buchnera aphidicola

Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona 85721

Received 21 January 2005/ Accepted 7 March 2005

Buchnera aphidicola, the obligate symbiont of aphids, has an extremely reduced genome, of which about 10% is devoted to the biosynthesis of essential amino acids needed by its hosts. Most regulatory genes for these pathways are absent, raising the question of whether and how transcription of these genes responds to the major shifts in dietary amino acid content encountered by aphids. Using full-genome microarrays for B. aphidicola of the host Schizaphis graminum, we examined transcriptome responses to changes in dietary amino acid content and then verified behavior of individual transcripts using quantitative reverse transcriptase PCR. The only gene showing a consistent and substantial (>twofold) response was metE, which underlies methionine biosynthesis and which is the only amino acid biosynthetic gene retaining its ancestral regulator (metR). In another aphid host, Acyrthosiphon pisum, B. aphidicola has no functional metR and shows no response in metE transcript levels to changes in amino acid concentrations. Thus, the only substantial transcriptional response involves the one gene for which an ancestral regulator is retained. This result parallels that from a previous study on heat stress, in which only the few genes retaining the global heat shock promoter showed responses in transcript abundance. The irreversible losses of transcriptional regulators constrain ability to alter gene expression in the context of environmental fluctuations affecting the symbiotic partners.

This article has been cited by other articles:

• Molina, N., van Nimwegen, E. (2008). Universal patterns of purifying selection at noncoding positions in bacteria. Genome Res. 18: 148-160 [Abstract] [Full Text]  
• Reymond, N., Calevro, F., Vinuelas, J., Morin, N., Rahbe, Y., Febvay, G., Laugier, C., Douglas, A., Fayard, J.-M., Charles, H. (2006). Different Levels of Transcriptional Regulation Due to Trophic Constraints in the Reduced Genome of Buchnera aphidicola APS. Appl. Environ. Microbiol. 72: 7760-7766 [Abstract] [Full Text]  
• Bulach, D. M., Zuerner, R. L., Wilson, P., Seemann, T., McGrath, A., Cullen, P. A., Davis, J., Johnson, M., Kuczek, E., Alt, D. P., Peterson-Burch, B., Coppel, R. L., Rood, J. I., Davies, J. K., Adler, B. (2006). Genome reduction in Leptospira borgpetersenii reflects limited transmission potential. Proc. Natl. Acad. Sci. USA 103: 14560-14565 [Abstract] [Full Text]  
• Zientz, E., Beyaert, I., Gross, R., Feldhaar, H. (2006). Relevance of the Endosymbiosis of Blochmannia floridanus and Carpenter Ants at Different Stages of the Life Cycle of the Host. Appl. Environ. Microbiol. 72: 6027-6033 [Abstract] [Full Text]  
• Huerta, A. M., Collado-Vides, J., Francino, M. P. (2006). Positional Conservation of Clusters of Overlapping Promoter-Like Sequences in Enterobacterial Genomes. Mol Biol Evol 23: 997-1010 [Abstract] [Full Text]  
• Moran, N. A., Degnan, P. H., Santos, S. R., Dunbar, H. E., Ochman, H. (2005). Inaugural Article: The players in a mutualistic symbiosis: Insects, bacteria, viruses, and virulence genes. Proc. Natl. Acad. Sci. USA 102: 16919-16926 [Abstract] [Full Text]  
• Minezaki, Y., Homma, K., Nishikawa, K. (2005). Genome-Wide Survey of Transcription Factors in Prokaryotes Reveals Many Bacteria-Specific Families Not Found in Archaea. DNA Res 12: 269-280 [Abstract] [Full Text]