Studying the role of sRNAs in post-transcriptional regulation of stress response in Caulobacter.

• Grant number: 24/20406-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2025
• End date: January 31, 2027
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Marilis Do Valle Marques
• Grantee: Phelipe Augusto Borba Martins Peres
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 21/10577-0 - Biology of Bacteria and Bacteriophages Research Center, AP.CEPID

Abstract

To ensure a rapid and effective response to stress, a network of transcription factors and regulatory small RNAs (sRNAs) regulate gene expression by transcriptional and post-transcriptional mechanisms. Small regulatory RNAs regulate gene expression post-transcriptionally via base-pairing interactions with the targets, usually at the mRNA 5'-Untranslated Region, and so altering their stability and/or translation of the mRNA. We have determined the C. crescentus OxyR regulon by global transcriptomics analysis in response to hydrogen peroxide. A single sRNA-encoding gene, CCNA_R0080, coding for the new sRNA OsrA, was induced by H2O2 in a OxyR-independent manner. This sRNA was predicted to interact with several distinct mRNAs, suggesting it is a mediator of a new regulatory network that controls the oxidative stress response via post-transcriptional regulation. Our hypothesis is that the sRNA OsrA has a major role in the regulation of oxidative stress response, binding and altering the stability and translation of several mRNAs, which will be investigated in this project. The increased stabilization of mRNA secondary structures affects mainly its half-life and translation initiation, causing a dramatic change in the patterns of gene expression. To overcome these deleterious effects and adapt to low temperature conditions, bacteria express a distinct set of proteins that will help adjust the fluidity of the cell membrane, minimize RNA secondary structures and resume growth. We have determined the global transcriptome in response to cold stress, and several sRNAs were highly induced at low temperature. We will evaluate their role in stress gene regulation via binding and altering the stability and translation of mRNAs.