| Grant number: | 14/04046-8 |
| Support type: | Research Projects - Thematic Grants |
| Duration: | September 01, 2014 - August 31, 2019 |
| Field of knowledge: | Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms |
| Principal researcher: | Marilis Do Valle Marques |
| Grantee: | Marilis Do Valle Marques |
| Home Institution: | Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| Assoc. researchers: | Bonaventura Francesco Luisi ; Phillip E. Klebba ; Tie Koide |
| Associated scholarship(s): | 18/17309-8 - Study of the role of the DEAD-box RNA helicase RhlB in the RNA stability and gene expression in Caulobacter crescentus,
BP.DR 17/02127-9 - Characterization of iron transport systems in Caulobacter crescentus, BP.MS 16/06378-3 - Characterization of the DEAD-box RNA helicase CC1478 in Caulobacter crescentus and its regulation, BP.MS + associated scholarships - associated scholarships |
Abstract
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)