کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2187063 | 1096095 | 2008 | 18 صفحه PDF | دانلود رایگان |

The appearance of atmospheric oxygen from photosynthetic activity led to the evolution of aerobic respiration and responses to the resulting reactive oxygen species. In Rhodobacter sphaeroides, a photosynthetic α-proteobacterium, a transcriptional response to the reactive oxygen species singlet oxygen (1O2) is controlled by the group IV σ factor σE and the anti-σ factor ChrR. In this study, we integrated various large datasets to identify genes within the 1O2 stress response that contain σE-dependent promoters both within R. sphaeroides and across the bacterial phylogeny. Transcript pattern clustering and a σE-binding sequence model were used to predict candidate promoters that respond to 1O2 stress in R. sphaeroides. These candidate promoters were experimentally validated to nine R. sphaeroides σE-dependent promoters that control the transcription of 15 1O2-activated genes. Knowledge of the R. sphaeroides response to 1O2 and its regulator σE–ChrR was combined with large-scale phylogenetic and sequence analyses to predict the existence of a core set of approximately eight conserved σE-dependent genes in α-proteobacteria and γ-proteobacteria. The bacteria predicted to contain this conserved response to 1O2 include photosynthetic species, as well as free-living and symbiotic/pathogenic nonphotosynthetic species. Our analysis also predicts that the response to 1O2 evolved within the time frame of the accumulation of atmospheric molecular oxygen on this planet.
Journal: Journal of Molecular Biology - Volume 383, Issue 3, 14 November 2008, Pages 713–730