Characterization of new regulatory circuits for gene expression in Alphaproteobacteria

• Grant number: 22/06360-8
• Support Opportunities: Regular Research Grants
• Start date: September 01, 2022
• End date: February 28, 2025
• Field of knowledge: Biological Sciences - Genetics - Molecular Genetics and Genetics of Microorganisms
• Principal Investigator: Marilis Do Valle Marques
• Grantee: Marilis Do Valle Marques
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Marcio Vinicius Bertacine Dias ; Tie Koide

Abstract

The transcription initiation is the most important regulatory step of gene expression, carried out by the transcription factors, but recent literature has increasingly reported the importance of post-transcriptional gene regulation. Among the most studied mechanisms are those mediated by small regulatory RNAs and RNA-binding proteins, that alter the stability and translation properties of the target RNAs. These systems are still poorly characterized in bacteria other than the model E. coli, especially in more distant phylogenetic groups. This project aims to characterize some of the regulatory mechanisms of Caulobacter crescentus, a free-living non-pathogenic species with well-established genetic tools, as a model for the alphaproteobacterial group. The understanding of the regulatory mechanisms of this group, being conserved among species, has large potential for use in other species of interest. The alphaproteobacteria are a large group comprising many interesting genear, such as pathogens to humans and animals (Brucella, Bartonella, Ricketsia), phytopathogens (Agrobacterium), nitrogen fixing (Beijerinckia, Rhizobium) and symbionts to plants and insects (Rhizobium, Wolbachia).In C. crescentus about 133 sRNAs were predicted by in silico analyses, but only four have been characterized so far, so we propose to study the role of some sRNAs putatively involved in regulating stress response genes. The role of the transcription regulator IscR in the expression of genes for the synthesis of the Fe-S group and other genes important for iron homeostasis will be determined. In C. crescentus the enzyme aconitase is associated with the RNA degradosome, indicating that it has a broader regulatory role, since no regulatory sRNA for iron homeostasis has been identified. Therefore, we will evaluate the regulatory role of aconitase on gene expression, more specially on iron metabolism. Two conserved genes encoding proteins of unknown function are repressed by Fe-FUR and highly induced at iron starvation, and the role of these proteins as a new iron signaling system will be investigated. (AU)

Scientific publications

(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)

DOS SANTOS, NAARA M.; PICINATO, BEATRIZ A.; SANTOS, LUCAS S.; DE ARAUJO, HUGO L.; BALAN, ANDREA; KOIDE, TIE; MARQUES, MARILIS V.. Mapping the IscR regulon sheds light on the regulation of iron homeostasis in Caulobacter. FRONTIERS IN MICROBIOLOGY, v. 15, p. 18-pg., 2024-09-30. (21/10577-0, 22/00308-4, 20/10171-0, 22/06360-8, 18/17309-8)

DE ARAUJO, HUGO L.; PICINATO, BEATRIZ A.; LORENZETTI, ALAN P. R.; MUTHUNAYAKE, NISANSALA S.; RATHNAYAKA-MUDIYANSELAGE, I. W.; DOS SANTOS, NAARA M.; SCHRADER, JARED; KOIDE, TIE; MARQUES, MARILIS V.. The DEAD-box RNA helicase RhlB is required for efficient RNA processing at low temperature in Caulobacter. MICROBIOLOGY SPECTRUM, v. 11, n. 6, p. 20-pg., 2023-10-18. (21/10577-0, 17/03052-2, 19/08514-0, 22/00308-4, 22/06360-8, 18/17309-8)