Srn_9342: A non-canonical Staphylococcus aureus regulatory RNA with potential role in virulence
The emergence of bacterial pathogens multi-resistant to antibiotics is a major public health issue. In Europe, 33,000 people die every year from bacteria resistant to antibiotics, including 7,000 dues to Staphylococcus aureus. S. aureus is a human commensal but also a deadly pathogen. During the transition from colonization to infection, bacteria finely reprogram gene expression via transcription factors and regulatory RNAs (sRNAs). The latter are involved in various processes, including virulence and resistance to antibiotics. While they were originally considered as expressed from the intergenic regions or in the opposite direction from their targets, several examples show that some escape this rule (Wang et al, 2019). Our work on S. aureus led to the establishment of a database on regulatory RNAs (Sassi et al, 2015; srd.genouest.org) and then, to the identification of novel sRNAs (Bronsard et al, 2017). One of them, Srn_9342, has atypical features. It is one of the first example of an sRNA expressed in S. aureus with two distinct forms from the 3’ region of a mRNA.
The internship project will focus on the characterization of Srn_9342 and the determination of its functions in the bacterium. We already identified RNA targets by affinity coupled to high-throughput sequencing (MAPS), and showed that the deletion of srn_9342 increases S. aureus virulence in an invertebrate model of infection revealed and modify the RNA level of some targets during culture in optimal conditions. We also showed that Srn_9342 expression is ϬB-dependent. Currently, we are working on a chromosomal complementation to strengthen our investigations.
During the internship, the applicant will work in close interaction with a 2nd year PhD student. Based on our own progress, the trainee will work on (i) deciphering the boundaries of Srn_9342 mRNA targets, (ii) performing infection studies on an invertebrate model of infection, (iii) studying the effect of Srn_9342 overexpression using inducible plasmids, or (iv) investigate Srn_9342 expression using transcriptional fusion (β-lactamase assay).
The student must have strong interest for the biology of pathogen and for molecular biology and biochemistry. The student must have a pronounced taste for curiosity and demonstrate scientific rigor.
For more information regarding this internship do not hesitate to contact me at yoann [dot] augagneur
univ-rennes1 [dot] fr
