Category Archives: Uncategorized

Nucleic Acids Res, auth.: group Roignant

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Comprehensive map of ribosomal 2′-O-methylation and C/D box snoRNAs in Drosophila melanogaster

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.

Abstract

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.

Welcome to Karine Baumer !

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Bonjour à tous,

je viens de joindre le groupe du Prof. Johannes Larsch en tant que Lab Technician.

J’ai un backgrund principalement en gestion de laboratoire, qualité et en biologie moléculaire dans la recherche contre le cancer et en génétique forensique.

Je suis l’heureuse maman d’un petit garçon de 5 ans avec qui j’aime partager mes passions pour le ski, la nature, le camping et surtout griller un bon cervelas au coin du feu !

Au plaisir de vous rencontrer tous et de vous découvrir!

Karine

Welcome to Danin Dharmaperwira !

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Hi everyone, my name is Danin and I recently started at the Larsch lab. 
In addition to my love for spicy foods, I leave you with some spicy opinions:

  • Spaghetti is pasta for adults, those who cut it are children
  • Cats are cute, but slightly overrated
  • Out of all fruits, the banana is the best

Please feel encouraged to debate whether you agree with these opinions.

Welcome to Yoëlle Hilbers !

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Hi everyone! I am Yoëlle Hilbers, a plant biologist from the Netherlands. I studied Biology (Bachelor) and Molecular & Cellular Life Sciences (Master) at Utrecht University, where I did research on how bolting and rosette growth habit are regulated by ATH1 and PIF4 in the Shoot Apical Meristem. To finish of my Master’s, I also did an internship at Stanford University where I studied development of stomata under the regulation of SPCH and FAMA.

Now, I am happy to join Prof. Christian Fankhauser’s lab as a PhD student, to continue working on light regulated plant growth and development!

Some things about me: I love spending time in nature, and I am looking forward to do a lot of hikes in the area and swimming in Lac Léman! I also enjoy being creative (painting/photography), and like to combine work and art by making scientific illustrations 🙂

I hope to see you around!

Cells, co-auth.:W.Wahli

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The Opioid Receptor Influences Circadian Rhythms in Human Keratinocytes through the β-Arrestin Pathway

Paul Bigliardi 1 2, Seetanshu Junnarkar 3, Chinmay Markale 1 2, Sydney Lo 1 2, Elena Bigliardi 1 2, Alex Kalyuzhny 4, Sheena Ong 3, Ray Dunn 3 5, Walter Wahli 5 6 7, Mei Bigliardi-Qi 1 2

. 2024 Jan 25;13(3):232.

 doi: 10.3390/cells13030232.

Abstract

The recent emphasis on circadian rhythmicity in critical skin cell functions related to homeostasis, regeneration and aging has shed light on the importance of the PER2 circadian clock gene as a vital antitumor gene. Furthermore, delta-opioid receptors (DOPrs) have been identified as playing a crucial role in skin differentiation, proliferation and migration, which are not only essential for wound healing but also contribute to cancer development. In this study, we propose a significant association between cutaneous opioid receptor (OPr) activity and circadian rhythmicity. To investigate this link, we conducted a 48 h circadian rhythm experiment, during which RNA samples were collected every 5 h. We discovered that the activation of DOPr by its endogenous agonist Met-Enkephalin in N/TERT-1 keratinocytes, synchronized by dexamethasone, resulted in a statistically significant 5.6 h delay in the expression of the core clock gene PER2. Confocal microscopy further confirmed the simultaneous nuclear localization of the DOPr-β-arrestin-1 complex. Additionally, DOPr activation not only enhanced but also induced a phase shift in the rhythmic binding of β-arrestin-1 to the PER2 promoter. Furthermore, we observed that β-arrestin-1 regulates the transcription of its target genes, including PER2, by facilitating histone-4 acetylation. Through the ChIP assay, we determined that Met-Enkephalin enhances β-arrestin-1 binding to acetylated H4 in the PER2 promoter. In summary, our findings suggest that DOPr activation leads to a phase shift in PER2 expression via β-arrestin-1-facilitated chromatin remodeling. Consequently, these results indicate that DOPr, much like its role in wound healing, may also play a part in cancer development by influencing PER2.

Front Mol Biosci, Auth.: AM Cattaneo, group Benton

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Heterologous investigation of metabotropic and ionotropic odorant receptors in ab3A neurons of Drosophila melanogaster

Johan Henning Pettersson 1, Alberto Maria Cattaneo 1 2 3

. 2024 Jan 25:10:1275901.

 doi: 10.3389/fmolb.2023.1275901. eCollection 2023.

Abstract

In insects, antennal ionotropic receptors (IRs) and odorant receptors (ORs) are among the main sensors of olfactory cues. To functionally characterize the subunits from these receptors, the use of ab3A neurons from transgenic Drosophila melanogaster represented one of the most powerful tools, allowing the identification of ligands (deorphanization) and decrypting their pharmacological properties. However, further investigation is needed to shed light on possible metabotropic functionalities behind insect olfactory receptors and test potentials from the up-to-now-used empty neuronal systems to express subunits belonging to variegate receptor classes. In this project, we adopted the most updated system of Drosophila ab3A empty neurons to test various olfactory receptors, ranging from human ORs working as metabotropic G-protein coupled receptors to insect ionotropic IRs and ORs. Testing transgenic Drosophila expressing human ORs into ab3A neurons by single sensillum recording did not result in an OR response to ligands, but it rather re-established neuronal spiking from the empty neurons. When transgenic D. melanogaster expressed ionotropic IRs and ORs, both heterologous and cis-expressed IRs were non-functional, but the Drosophila suzukii OR19A1 subunit responded to a wide asset of ligands, distinguishing phasic or tonic compound-dependent effects. Despite the use of Drosophila ab3A neurons to test the activation of some metabotropic and ionotropic receptor subunits resulted non-functional, this study deorphanized a key OR of D. suzukii demonstrating its binding to alcohols, ketones, terpenes, and esters.