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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Stress response regulators identified through genome-wide transcriptome analysis of the (p) ppGpp-dependent response in Rhizobium etli. | Vercruysse et al. Genome Biology 2011 12 R17 http genomebiology.eom 2011 12 2 R17 w Genome Biology RESEARCH Open Access Stress response regulators identified through genome-wide transcriptome analysis of the p ppGpp-dependent response in Rhizobium etli Maarten Vercruysse Maarten Fauvart Ann Jans Serge Beullens Kristien Braeken Lore Cloots Kristof Engelen Kathleen Marchal and Jan Michiels Abstract Background The alarmone p ppGpp mediates a global reprogramming of gene expression upon nutrient limitation and other stresses to cope with these unfavorable conditions. Synthesis of p ppGpp is in most bacteria controlled by RelA SpoT Rsh proteins. The role of p ppGpp has been characterized primarily in Escherichia coli and several Gram-positive bacteria. Here we report the first in-depth analysis of the p ppGpp-regulon in an a-proteobacterium using a high-resolution tiling array to better understand the pleiotropic stress phenotype of a relA rsh mutant. Results We compared gene expression of the Rhizobium etli wild type and rsh previously rel mutant during exponential and stationary phase identifying numerous p ppGpp targets including small non-coding RNAs. The majority of the 834 p ppGpp-dependent genes were detected during stationary phase. Unexpectedly 223 genes were expressed p ppGpp-dependently during early exponential phase indicating the hitherto unrecognized importance of p ppGpp during active growth. Furthermore we identified two p ppGpp-dependent key regulators for survival during heat and oxidative stress and one regulator putatively involved in metabolic adaptation namely extracytoplasmic function sigma factor EcfG2 PF00052 transcription factor CH00371 and serine protein kinase PrkA. Conclusions The regulatory role of p ppGpp in R. etli stress adaptation is far-reaching in redirecting gene expression during all growth phases. Genome-wide transcriptome analysis of a strain deficient in a global regulator and exhibiting a pleiotropic phenotype enables the .
