Details

Autor(en) / Beteiligte

• Blanchard, Jeffrey L
• Wholey, Wei-Yun
• Conlon, Erin M
• Pomposiello, Pablo J
• Sonenshein, Abraham

Titel

Rapid changes in gene expression dynamics in response to superoxide reveal SoxRS-dependent and independent transcriptional networks

Ist Teil von

• PloS one, 2007-11, Vol.2 (11), p.e1186

Ort / Verlag

United States: Public Library of Science

Erscheinungsjahr

2007

Quelle

MEDLINE

Beschreibungen/Notizen

• SoxR and SoxS constitute an intracellular signal response system that rapidly detects changes in superoxide levels and modulates gene expression in E. coli. A time series microarray design was used to identify co-regulated SoxRS-dependent and independent genes modulated by superoxide minutes after exposure to stress. soxS mRNA levels surged to near maximal levels within the first few minutes of exposure to paraquat, a superoxide-producing compound, followed by a rise in mRNA levels of known SoxS-regulated genes. Based on a new method for determining the biological significance of clustering results, a total of 138 genic regions, including several transcription factors and putative sRNAs were identified as being regulated through the SoxRS signaling pathway within 10 minutes of paraquat treatment. A statistically significant two-block SoxS motif was identified through analysis of the SoxS-regulated genes. The SoxRS-independent response included members of the OxyR, CysB, IscR, BirA and Fur regulons. Finally, the relative sensitivity to superoxide was measured in 94 strains carrying deletions in individual, superoxide-regulated genes. By integrating our microarray time series results with other microarray data, E. coli databases and the primary literature, we propose a model of the primary transcriptional response containing 226 protein-coding and sRNA sequences. From the SoxS dependent network the first statistically significant SoxS-related motif was identified.