The Terminal Extensions of Dbp7 Influence Growth and 60S Ribosomal Subunit Biogenesis in Saccharomyces cerevisiae

Ribosome synthesis is a complex process that involves a large set of protein trans-acting factors, among them DEx(D/H)-box helicases. These are enzymes that carry out remodelling activities onto RNAs by hydrolysing ATP. The nucleolar DEGD-box protein Dbp7 is required for the biogenesis of large 60S ribosomal subunits. Recently, we have shown that Dbp7 is an RNA helicase that regulates the dynamic base-pairing between the snR190 small nucleolar RNA and the precursors of the ribosomal RNA within early pre-60S ribosomal particles. As the rest of DEx(D/H)-box proteins, Dbp7 has a modular organization formed by a helicase core region, which contains conserved motifs, and variable, non-conserved N- and C-terminal extensions. The role of these extensions remains unknown. Herein, we show that the N-terminal domain of Dbp7 is necessary for efficient nuclear import of the protein. Indeed, a basic bipartite nuclear localization signal (NLS) could be identified in its N-terminal domain. Removal of this putative NLS impairs, but does not abolish, Dbp7 nuclear import. Both N- and C-terminal domains are required for normal growth and 60S ribosomal subunit synthesis. Furthermore, we have studied the role of these domains in the association of Dbp7 with pre-ribosomal particles. Altogether, our results show that the N- and C-terminal domains of Dbp7 are important for the optimal function of this protein during ribosome biogenesis.Ministerio de Ciencia e Innovación PID2019-103850-GB-I00Junta de Andalucía P20_00581, BIO-271, BIO-210Universidad de Sevilla US-138039

Association of snR190 snoRNA chaperone with early pre-60S particles is regulated by the RNA helicase Dbp7 in yeast

Synthesis of eukaryotic ribosomes involves the assembly and maturation of precursor particles (pre-ribosomal particles) containing ribosomal RNA (rRNA) precursors, ribosomal proteins (RPs) and a plethora of assembly factors (AFs). Formation of the earliest precursors of the 60S ribosomal subunit (pre-60S r-particle) is among the least understood stages of ribosome biogenesis. It involves the Npa1 complex, a protein module suggested to play a key role in the early structuring of the pre-rRNA. Npa1 displays genetic interactions with the DExD-box protein Dbp7 and interacts physically with the snR190 box C/D snoRNA. We show here that snR190 functions as a snoRNA chaperone, which likely cooperates with the Npa1 complex to initiate compaction of the pre-rRNA in early pre-60S r-particles. We further show that Dbp7 regulates the dynamic base-pairing between snR190 and the pre-rRNA within the earliest pre-60S r-particles, thereby participating in structuring the peptidyl transferase center (PTC) of the large ribosomal subunit.The Henry/Henras group is supported by grants from ANR (ANR-20-CE12-0026) and funding from CNRS and University of Toulouse. R.A.M. is supported by grants from the Rectorat of Lebanese University. M.J. is supported by a Ph.D. fellowship from the Lebanese University and CIOES Organization. The group of J.d.l.C. is supported by the Spanish Ministry of Science and Innovation [PID2019-103859-GB-I00 AEI/ 10.13039/501100011033], and the Andalusian Regional Government (JA; BIO-271). J.C. was supported by a Ph.D. fellowship (PIF) from the University of Seville, and S.M.-V. is an academic research staff of the JA (PAIDI2020). M.T.B. and K.E.B. are supported by funding from the Deutsche Forschungsgemeinschaft (SFB860) and the University Medical Centre Göttingen

[Facial dermatosis: acne, rosacea, seborrhoeic dermatitis]

International audienc

Dosage des opiacés, de la cocaïne, des dérivés amphétaminiques et de leurs métabolites dans le sang total par SPE-UPLC/MS/MS

Objectif : Développer une méthode de préparation d’échantillons et de quantification simultanée des opiacés, des dérivés amphétaminiques, de la cocaïne et de leurs métabolites dans le sang total par SPE-UPLC/MS-MS. Méthode : 200 μL de sang total préalablement déprotéinisés sont extraits sur cartouches Oasis® MCX (SPE). Les échantillons sont analysés sur une colonne Acquity UPLCTM BEH C18, 1,7 μm (2,1  ×  100 mm) éluée par un gradient d’acide formique 0,1 % et d’acétonitrile. Les composés sont détectés au moyen d’un spectromètre de masse en tandem en utilisant deux transitions (MRM). Résultats : La méthode développée est sensible et linéaire de 1 à 500 ng/mL pour l’ensemble des molécules avec une précision inter et intra-séries (CV <20 %). Les limites de détection varient de 0,17 à 2,07 ng/mL selon les composés. Conclusion : Une méthode de préparation d’échantillons couplée à l’UPLC/MS-MS est développée pour identifier et quantifier simultanément trois familles de stupéfiants dans le sang total. Cette méthode rapide et sensible est une bonne alternative aux méthodes de chromatographie en phase gazeuse qui nécessitent une dérivation supplémentaire lors du prétraitement

Primary cutaneous lymphomas: a population-based descriptive study of 71 consecutive cases diagnosed between 1980 and 2003.

International audienceAlthough primary cutaneous lymphomas (PCL) are the second most common group of extra-nodal non-Hodgkin lymphomas, few epidemiological data are available in the literature, and most of them are provided by large databases from population-based cancer registries in the US or patients attending a single institution. We conducted this study to investigate the epidemiological and clinical features of PCL diagnosed in the department of Doubs from 1980 to 2003. Data were collected from the Doubs cancer registry from 1980 to 2003. Seventy-one patients with PCL were investigated. 82% were cutaneous T-cell lymphoma (CTCL) and 18% were cutaneous B-cell lymphoma (CBCL). Among CTCL, mycosis fungoides (MF) represented 58% and Sezary syndrome 10%. The standardised incidence rate of PCL was 0.42 for 100 000 person-years and significantly increased from 0.21 in 1980-1984 to 0.70 in 2000-2003 (p <0.05). The incidence rate of CTCL was 0.34 for 100 000 person-year and significantly increased from 0.2 to 0.57 (p <0.05). For MF and CBCL, the incidence rates were 0.20 and 0.08, respectively and did not vary significantly from 1980-1984 to 2000-2003. Five-year survival was 64.5% for PCL patients similar to MF patients. Our results provide updated data on the incidence of PCL in France