Missions

Understanding the mechanisms of processing, modification, and quality control of ribosomal RNAs in Bacillus subtilis

An 18-month postdoctoral position is available in the group "Biogenesis, architecture, and interactions of RNAs", led by Carine Tisné at the Institut de Biologie Physico-Chimique (IBPC), located in the heart of Paris. The researcher will take part in the ANR-funded project ARNr-PMQC. The postdoc will study the molecular mechanisms of post-transcriptional modifications of B. subtilis ribosomal RNAs, in collaboration with Ciaran Condon's team.

Ribosomes are essential ribonucleoprotein complexes responsible for protein synthesis. The ARNr-PMQC project addresses new questions related to the processing, post-transcriptional modifications (PTMs), and quality control (QC) of ribosomal RNAs (rRNAs) in the Firmicutes model organism B. subtilis. rRNA maturation involves the processing of 5′ and 3′ extensions by ribonucleases (RNases) and the addition of PTMs by modifying enzymes. In Bacillus, many of these steps rely on ribosomal proteins as cofactors, thereby linking rRNA maturation to QC of proper ribosome assembly. In this project, we aim to resolve the structures of rRNA maturation complexes involving both RNases and modification enzymes, and to explore a novel QC link between rRNA modification and mRNA stability through ribosome stalling.

Related publication:
Oerum S, Dendooven T, Catala M, Gilet L, Dégut C, Trinquier A, Bourguet M, Barraud P, Cianferani S, Luisi BF, Condon C, Tisné C. (2020), Structures of B. subtilis Maturation RNases Captured on 50S Ribosome with Pre-rRNAs. Mol Cell. 80(2):227–236. doi: 10.1016/j.molcel.2020.09.008.

Activités

Main activities
Cryo-EM: sample preparation (grid making), screening, data collection on electron microscopes, and data processing
Structural modeling and refinement
Training and supervising team members (1 research engineer, 1 postdoc) in Cryo-EM: sample prep, data processing, and model building/refinement
Biochemistry: protein and RNA purification, in vitro transcription, preparation of RNA–protein complexes, enzymatic assays

Compétences

Skills required
Knowledge
Expertise in RNA–protein complex Cryo-EM
General knowledge of biochemistry (enzymology, protein and RNA purification, etc.)
Experience in supervising others
Fluent scientific English

Know-how
Planning and conducting structural analysis
Organizing daily work with team members
Presenting results clearly and sharing technical expertise

Soft skills
Motivation to supervise and share knowledge
Team spirit and supportive supervision
Open-minded, curious, with strong synthesis skills
Well-organized and detail-oriented
Critical thinking and scientific integrity

Contexte de travail

Working environment
All experiments will be conducted at the CNRS within the IBPC, on the Curie campus in the 5th arrondissement of Paris, or at electron microscopy facilities for data collection (Institut Curie, Institut Pasteur, IGBMC, SOLEIL, ESRF…). All necessary equipment is available in the lab or nearby.
The IBPC hosts five research units and one research federation. The team led by C. Tisné is part of the Microbial Gene Expression unit and currently consists of seven members (2 researchers, 2 research engineers, 2 PhD students, and 1 postdoc).