Hello everyone,
My name is Lise Rolée and I recently started as an Administrative Assistant. I will be in charge of the groups of Alexandre Reymond, Richard Benton, Johannes Larsch and Jean-Yves Roignant.
I worked for 6 years in the Department of Fundamental Neurosciences in the same position, where I learned a lot. I’m happy to be able to share it with you!
I’m looking forward to meeting you all,
Fabien Sénéchal 1 2, Sarah Robinson 3 4, Evert Van Schaik 5 6, Martine Trévisan 1, Prashant Saxena 1 7, Didier Reinhardt 5, Christian Fankhauser 1
. 2024 Apr 21;8(4):e584.
doi: 10.1002/pld3.584. eCollection 2024 Apr.
Plants growing with neighbors compete for light and consequently increase the growth of their vegetative organs to enhance access to sunlight. This response, called shade avoidance syndrome (SAS), involves photoreceptors such as phytochromes as well as phytochrome interacting factors (PIFs), which regulate the expression of growth-mediating genes. Numerous cell wall-related genes belong to the putative targets of PIFs, and the importance of cell wall modifications for enabling growth was extensively shown in developmental models such as dark-grown hypocotyl. However, the contribution of the cell wall in the growth of de-etiolated seedlings regulated by shade cues remains poorly established. Through analyses of mechanical and biochemical properties of the cell wall coupled with transcriptomic analysis of cell wall-related genes from previously published data, we provide evidence suggesting that cell wall modifications are important for neighbor proximity-induced elongation. Further analysis using loss-of-function mutants impaired in the synthesis and remodeling of the main cell wall polymers corroborated this. We focused on the cgr2cgr3 double mutant that is defective in methylesterification of homogalacturonan (HG)-type pectins. By following hypocotyl growth kinetically and spatially and analyzing the mechanical and biochemical properties of cell walls, we found that methylesterification of HG-type pectins was required to enable global cell wall modifications underlying neighbor proximity-induced hypocotyl growth. Collectively, our work suggests that plant competition for light induces changes in the expression of numerous cell wall genes to enable modifications in biochemical and mechanical properties of cell walls that contribute to neighbor proximity-induced growth.
Athena Sklias 1, Sonia Cruciani 2, Virginie Marchand 3, Mariangela Spagnuolo 4, Guillaume Lavergne 1, Valérie Bourguignon 3, Alessandro Brambilla 5, René Dreos 1, Steven J Marygold 6, Eva Maria Novoa 2 7, Yuri Motorin 3, Jean-Yves Roignant 1 4
. 2024 Apr 12;52(6):2848-2864.
doi: 10.1093/nar/gkae139.
During their maturation, ribosomal RNAs (rRNAs) are decorated by hundreds of chemical modifications that participate in proper folding of rRNA secondary structures and therefore in ribosomal function. Along with pseudouridine, methylation of the 2′-hydroxyl ribose moiety (Nm) is the most abundant modification of rRNAs. The majority of Nm modifications in eukaryotes are placed by Fibrillarin, a conserved methyltransferase belonging to a ribonucleoprotein complex guided by C/D box small nucleolar RNAs (C/D box snoRNAs). These modifications impact interactions between rRNAs, tRNAs and mRNAs, and some are known to fine tune translation rates and efficiency. In this study, we built the first comprehensive map of Nm sites in Drosophila melanogaster rRNAs using two complementary approaches (RiboMethSeq and Nanopore direct RNA sequencing) and identified their corresponding C/D box snoRNAs by whole-transcriptome sequencing. We de novo identified 61 Nm sites, from which 55 are supported by both sequencing methods, we validated the expression of 106 C/D box snoRNAs and we predicted new or alternative rRNA Nm targets for 31 of them. Comparison of methylation level upon different stresses show only slight but specific variations, indicating that this modification is relatively stable in D. melanogaster. This study paves the way to investigate the impact of snoRNA-mediated 2′-O-methylation on translation and proteostasis in a whole organism.
Tim Pollex 1 2, Adam Rabinowitz 1, Maria Cristina Gambetta 1 3, Raquel Marco-Ferreres 1, Rebecca R Viales 1, Aleksander Jankowski 1 4, Christoph Schaub 1, Eileen E M Furlong 5
Affiliations expand
. 2024 Apr;56(4):686-696.
doi: 10.1038/s41588-024-01678-x. Epub 2024 Mar 11.
To regulate expression, enhancers must come in proximity to their target gene. However, the relationship between the timing of enhancer-promoter (E-P) proximity and activity remains unclear, with examples of uncoupled, anticorrelated and correlated interactions. To assess this, we selected 600 characterized enhancers or promoters with tissue-specific activity in Drosophila embryos and performed Capture-C in FACS-purified myogenic or neurogenic cells during specification and tissue differentiation. This enabled direct comparison between E-P proximity and activity transitioning from OFF-to-ON and ON-to-OFF states across developmental conditions. This showed remarkably similar E-P topologies between specified muscle and neuronal cells, which are uncoupled from activity. During tissue differentiation, many new distal interactions emerge where changes in E-P proximity reflect changes in activity. The mode of E-P regulation therefore appears to change as embryogenesis proceeds, from largely permissive topologies during cell-fate specification to more instructive regulation during terminal tissue differentiation, when E-P proximity is coupled to activation.
Hello World,
I am Jaime López, a biomedical researcher. I studied Biochemistry (Bachelor) and Biomedicine (Master and PhD) at the University of Córdoba (Spain). During that time, I had the opportunity to investigate different metabolic pathologies, especially those related to obesity and its associated disorders (e.g., cancer).
In 2020, I received an EMBO short-term fellowship to work at the CIG (UNIL) for 3 months, and I was amazed by the city of Lausanne and its beautiful landscapes. Four years later, I am back in the Fajas’ lab, ready to unravel the mechanisms of resistance to cancer treatments.
Personally, I like to enjoy nature, fitness and historical culture, including its spiritual part.
See you on the fifth floor of the Génopode building!
Hi everyone,
My name is Virginie and I recently started as a bioinformatician in the group of David Gatfield.
I studied Bachelor and Master at UniL, and did my PhD at UniBas. I am happy to be back, especially for sailing on the *Léman* lake!
Looking forward to meeting you all,
Cheers,
Vi
