Blood cell production relies on the coordinated activities of hematopoietic stem cells (HSCs) and multipotent and lineage-restricted progenitors. Here, we identify Notchless (Nle) as a critical factor for HSC maintenance under both homeostatic and cytopenic conditions. Nle deficiency leads to a rapid and drastic exhaustion of HSCs and immature progenitors and failure to maintain quiescence in HSCs. In contrast, Nle is dispensable for cycling-restricted progenitors and differentiated cells. In yeast, Nle/Rsa4 is essential for ribosome biogenesis, and we show that its role in pre-60S subunit maturation has been conserved in the mouse. Despite its implication in this basal cellular process, Nle deletion affects ribosome biogenesis only in HSCs and immature progenitors. Ribosome biogenesis defects are accompanied by p53 activation, which causes their rapid exhaustion. Collectively, our findings establish an essential role for Nle in HSC and immature progenitor functions and uncover previously unsuspected differences in ribosome biogenesis that distinguish stem cells from restricted progenitor populations.
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http://dx.doi.org/10.1084/jem.20122019 | DOI Listing |
Microbiol Res
January 2025
National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China. Electronic address:
RNase III, a ubiquitously distributed endonuclease, plays an important role in RNA processing and functions as a global regulator of gene expression. In this study, we explored the role of RNase III in mediating the oxidative stress response in Synechocystis sp. PCC 6803.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 2 Allée Konrad Roentgen, 67084 Strasbourg, France.
The importance of Mg2+ ions for RNA structure and function cannot be overstated. Several attempts were made to establish a comprehensive Mg2+ binding site classification. However, such descriptions were hampered by poorly modelled ion binding sites as observed in a recent cryo-EM 1.
View Article and Find Full Text PDFNat Commun
January 2025
Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, PR China.
Hyperactivation of ribosome biogenesis (RiBi) drives cancer progression, yet the role of RiBi-associated proteins (RiBPs) in breast cancer (BC) is underexplored. In this study, we perform a comprehensive multi-omics analysis and reveal that assembly and maturation factors (AMFs), a subclass of RiBPs, are upregulated at both RNA and protein levels in BC, correlating with poor patient outcomes. In contrast, ribosomal proteins (RPs) do not show systematic upregulation across various cancers, including BC.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center, Houston, TX 77030, USA. Electronic address:
tRNA modifications are critical for several aspects of their functions, including decoding, folding, and stability. Using a multifaceted approach encompassing eCLIP-seq and nanopore tRNA-seq, we show that the human tRNA methyltransferase TRMT1L interacts with the component of the Rix1 ribosome biogenesis complex and binds to the 28S rRNA as well as to a subset of tRNAs. Mechanistically, we demonstrate that TRMT1L is responsible for catalyzing N2,N2-dimethylguanosine (mG) solely at position 27 of tRNA-Tyr-GUA.
View Article and Find Full Text PDFJ Cell Biol
February 2025
Department of Biochemistry, University of Colorado, Boulder, CO, USA.
Cajal bodies are essential sites for the biogenesis of small nuclear and nucleolar ribonucleoproteins. In this issue, Courvan and Parker discuss new work from Neugebauer and colleagues (https://doi.org/10.
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