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Regulatory networks of bacterial stress response


The sensing of environmental signals is crucial for the cell to reset its gene expression to face the changes in the environment. As the bacterial population grows, cells face a progressive reduction of nutrient availability that brings the need to respond resetting the metabolism to withstand a long starvation period. The main goal of this project is to identify the environmental signals, signal transduction systems and regulatory mechanisms important for stress response in the alpha-proteobacterium Caulobacter crescentus. This Gram-negative aquatic bacterium is well adapted to very low nutrient environments, and possesses a developmental cycle that includes a unique step of cell differentiation that is unusual in bacteria.The maintenance of RNA function under stress conditions is ensured by inducing proteins that modulate transcription, translation and RNA turnover. Small Cold Shock Proteins (CSP) are induced at low temperature and/or stationary phase, and act as RNA chaperones, facilitating translation under these conditions, and as gene regulators. Another important system in this response is composed by the DEAD RNA helicases, which are responsible for resolving the RNA secondary structures, enhancing translation. These enzymes also associate to RNA degrading systems (degradosome), and participate in the assembly of riboproteic structures, like ribosomes. This project will evaluate the regulatory systems that control CSPs gene expression at stationary phase, and the role of each DEAD RNA helicase in stress response.Aerobic bacteria have also to respond to an increase in the concentration of reactive oxygen species, especially when the population enters stationary phase. Homeostasis of iron and other redox-active metals is a main point in the maintenance of minimal levels of oxidative stress, and has to be strictly controlled via several regulatory mechanisms. Besides Fur and OxyR, small regulatory RNAs control the expression of genes for iron metabolism, and will be studied in this project. (AU)

Scientific publications (8)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
SILVA, LARISSA G.; LORENZETTI, ALAN P. R.; RIBEIRO, RODOLFO A.; ALVES, INGRID R.; LEADEN, LAURA; GALHARDO, RODRIGO S.; KOIDE, TIE; MARQUES, MARILIS V. OxyR and the hydrogen peroxide stress response in Caulobacter crescentus. Gene, v. 700, p. 70-84, JUN 5 2019. Web of Science Citations: 0.
ASSIS, NADINE G.; RIBEIRO, RODOLFO A.; DA SILVA, LARISSA G.; VICENTE, ALEXANDRE M.; HUG, ISABELLE; MARQUES, MARILIS V. Identification of Hfq-binding RNAs in Caulobacter crescentus. RNA BIOLOGY, v. 16, n. 6 MAR 2019. Web of Science Citations: 0.
LEADEN, LAURA; SILVA, LARISSA G.; RIBEIRO, RODOLFO A.; DOS SANTOS, NAARA M.; LORENZETTI, ALAN P. R.; ALEGRIA, THIAGO G. P.; SCHULZ, MARIANE L.; MEDEIROS, MARISA H. G.; KOIDE, TIE; MARQUES, V, MARILIS. Iron Deficiency Generates Oxidative Stress and Activation of the SOS Response in Caulobacter crescentus. FRONTIERS IN MICROBIOLOGY, v. 9, AUG 28 2018. Web of Science Citations: 5.
ALVES, INGRID R.; LIMA-NORONHA, MARCO A.; SILVA, LARISSA G.; FERNANDEZ-SILVA, FRANK S.; FREITAS, ALINE LUIZA D.; MARQUES, MARILIS V.; GALHARDO, RODRIGO S. Effect of SOS-induced levels of imuABC on spontaneous and damage-induced mutagenesis in Caulobacter crescentus. DNA Repair, v. 59, p. 20-26, NOV 2017. Web of Science Citations: 3.
AGUIRRE, ANGEL A.; VICENTE, ALEXANDRE M.; HARDWICK, STEVEN W.; ALVELOS, DANIELA M.; MAZZON, RICARDO R.; LUISI, BEN F.; MARQUES, MARILIS V. Association of the Cold Shock DEAD-Box RNA Helicase RhlE to the RNA Degradosome in Caulobacter crescentus. Journal of Bacteriology, v. 199, n. 13 JUL 2017. Web of Science Citations: 6.
BALHESTEROS, HELOISE; SHIPELSKIY, YAN; LONG, NOAH J.; MAJUMDAR, ARITRI; KATZ, BENJAMIN B.; SANTOS, NAARA M.; LEADEN, LAURA; NEWTON, SALETE M.; MARQUES, MARILIS V.; KLEBBA, PHILLIP E. TonB-Dependent Heme/Hemoglobin Utilization by Caulobacter crescentus HutA. Journal of Bacteriology, v. 199, n. 6 MAR 2017. Web of Science Citations: 5.
DA SILVA, CAROLINA A. P. T.; LOURENCO, ROGERIO F.; MAZZON, RICARDO R.; RIBEIRO, RODOLFO A.; MARQUES, MARILIS V. Transcriptomic analysis of the stationary phase response regulator SpdR in Caulobacter crescentus. BMC Microbiology, v. 16, APR 12 2016. Web of Science Citations: 6.
SANTOS, JULIANA S.; DA SILVA, CAROLINA A. P. T.; BALHESTEROS, HELOISE; LOURENCO, ROGERIO F.; MARQUES, MARILIS V. CspC regulates the expression of the glyoxylate cycle genes at stationary phase in Caulobacter. BMC Genomics, v. 16, AUG 27 2015. Web of Science Citations: 4.

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