Project description:Leukemogenesis requires enhanced self-renewal activity, which is induced by specific oncogenes. The underlying molecular mechanisms remain incompletely understood. We transduced mouse lineage negative bone marrow cells (enriched for hematopoietic stem and progenitor cells) with retrovirus expressing leukemic oncogene AML1-ETO9a, MYC and MLL-AF9 as well as empty vector (MIG). We found that all three oncogenes enhanced snoRNA formation. High abundance of snoRNAs was observed in primary human AML specimens with the notable exception of NPM1 mutant AML. Leukemogenesis by AML1-ETO required expression of the groucho related Amino Enhancer of Split (AES). AES functioned by inducing snoRNA/RNP formation via interaction with the RNA helicase DDX21. Similarly, loss of C/D box snoRNAs with concomitant loss of rRNA 2’-O-methylation resulted in decreased leukemia self-renewal potential.In summary, we identified C/D box snoRNAs and rRNA 2’-O-methylation as critical determinants of leukemic stem cell activity.
Project description:Leukemogenesis requires enhanced self-renewal activity, which is induced by specific oncogenes. The underlying molecular mechanisms remain incompletely understood. We measured snoRNA expression in human primary AML samples that contained determined leukemia stem cells frequency. We identified that expression of C/D box snoRNAs was closely associated with leukemia stem cell frequency.
Project description:Eukaryotic RNA polymerase II (RNAPII) transcribes mRNA genes and non-protein coding RNAs (ncRNAs) including small nuclear and nucleolar RNAs (sn/snoRNAs). In metazoans, RNAPII transcription of sn/snoRNAs is facilitated by a number of specialized complexes, but no such complexes have been discovered in yeast. It has been proposed that yeast sn/snoRNA promoters use the same factors as mRNA promoters, but the extent to which regulators of mRNA genes function at yeast sn/snoRNA genes is unclear. Here, we investigated a potential role for the Mediator complex, essential for mRNA gene transcription, in the transcription of sn/snoRNA genes. We found that the Mediator maps to most sn/snoRNA gene regulatory regions and that rapid depletion of the essential structural subunit Med14 strongly reduces RNAPII and TFIIB occupancy as well as nascent transcription of sn/snoRNA genes. Deletion of Med3 and Med15, subunits of the activator-interacting Mediator tail module, does not affect Mediator recruitment to or RNAPII and TFIIB occupancy of sn/snoRNA genes. Our analyses suggest that Mediator promotes PIC formation and transcription at sn/snoRNA genes, expanding the role of this critical regulator beyond its known functions in mRNA gene transcription and demonstrating further mechanistic similarity between the transcription of mRNA and sn/snoRNA genes.
Project description:We combined mRNA, small RNA and ribosome methylation sequencing to investigate snoRNA expression patterns in multiple myeloma and their association with different chromosomal aberrations. We identified snoRNAs dysregulated in molecular subgroups, with SNORD78 being highly expressed in gain1q patients and associated with poor prognosis. Our study shows that the expression of particular snoRNAs and methylation of specific snoRNA-guided rRNA sites are associated with specific chromosome gains, which are common elements in multiple myeloma.
Project description:To explore the role of small nucleolar RNA (snoRNA) on self-renewal of liver cancer stem cells (CSCs), we isolated liver CSCs (CD133+CD13+) and Non-CSCs (CD133-CD13-) from huamn liver tumor tissues.
Project description:Acute myeloid leukemia (AML) is a disease with poor outcome but patients harbouring certain chromosomal rearrangements or complex karyotypes have particularly adverse prognosis. For these patients, targeted therapies have not yet made a significant clinical impact. To understand the molecular landscape of poor risk AML we profiled 55 poor risk AML patients using a multiomics approach that included transcriptomics (n=39), proteomics (n=55), phosphoproteomics (n=55) and an ex vivo drug sensitivity screening (482 compounds tested in at least 30 patients). We identified a phosphoproteomics signature that define two biologically distinct groups of KMT2A rearranged leukaemia, which we term MLLGA and MLLGB. MLLGA presented increased DOT1L phosphorylation, HOXA gene expression, CDK1 activity and phosphorylation of proteins involved in RNA metabolism, replication and DNA damage when compared to MLLGB and no KMT2A rearranged samples. MLLGA was particularly sensitive to 15 compounds including genotoxic drugs and inhibitors of mitotic kinases and IMPDH relative to other cases. The expression of IMPDH2 and multiple nucleolar proteins was higher in MLLGA and correlated with the response to IMPDH inhibition in KMT2A rearranged leukaemia, suggesting a role of the nucleolar activity in sensitivity to IMPDH inhibition. In summary, our multilayer molecular profiling of poor risk AML matched to the response to hundreds of compounds identified a phosphoproteomics signature that define two biologically and phenotypically distinct groups of KMT2A rearranged leukaemia. These data provide a rationale for the development of specific therapies for KMT2A subgroups characterised by the MLLGA phosphoproteomics signature identified in this study.
Project description:Background: Small nucleolar RNAs (snoRNAs) are mid-size non-coding RNAs required for ribosomal RNA modification, implying a ubiquitous tissue distribution linked to ribosome synthesis. However, increasing numbers of studies identify extra-ribosomal roles of snoRNAs in modulating gene expression, suggesting more complex snoRNA abundance patterns. Therefore, there is a great need for mapping the snoRNome in different human tissues as the blueprint for snoRNA functions. Results: We used a low structure bias RNA-Seq approach to accurately quantify snoRNAs and compare them to the entire transcriptome in seven healthy human tissues (breast, ovary, prostate, testis, skeletal muscle, liver and brain). We identify 475 expressed snoRNAs categorized in two abundance classes that differ significantly in their function, conservation level and correlation with their host gene: 390 snoRNAs are uniformly expressed and 85 are enriched in the brain or reproductive tissues. Most tissue-enriched snoRNAs are embedded in lncRNAs and display strong correlation of abundance with them, whereas uniformly expressed snoRNAs are mostly embedded in protein-coding host genes and are mainly non- or anticorrelated with them. 59% of the non-correlated or anticorrelated protein-coding host gene/snoRNA pairs feature dual-initiation promoters, compared to only 16% of the correlated non-coding host gene/snoRNA pairs. Conclusions: Our results demonstrate that snoRNAs are not a single homogeneous group of housekeeping genes but include highly regulated tissue-enriched RNAs. Indeed, our work indicates that the architecture of snoRNA host genes varies to uncouple the host and snoRNA expressions in order to meet the different snoRNA abundance levels and functional needs of human tissues.
Project description:Ribosome biosynthesis plays a crucial role in regulating protein translation and is essential for cell growth and development in physiological progress. The progression and recurrence of Pterygia mainly occur due to the abnormal proliferation and migration of stromal Pterygia fibroblasts. Small nucleolar RNA U3 (U3 snoRNA), harboring the atypical C/D boxes, is involved in 18S ribosomal RNA (18S rRNA) synthesis; however, the mechanism of U3 snoRNA in Pterygia remains unclear. Methods: Primary HCFs and HPFs were separated and cultured from fresh conjunctival grafts and Pterygia tissues. The PLKO.1 lentiviral system and CRISPR/Cas9 recombinant construct were, respectively, used to overexpress and silence U3 snoRNA in HPF and HCF cells for further specific phenotypes analysis. RNA-seq and TMT-labeled quantitative protein mass spectrometry were utilized to evaluate the effect of U3 snoRNA on mRNA transcripts and protein synthesis. Results: Reduced U3 snoRNA in Pterygia promotes HCF or HPF cells' proliferation, migration, and cell cycle but has no significant effect on apoptosis. U3 snoRNA modulates 18S rRNA synthesis through shearing precursor ribosomal RNA 47S rRNA at the 5′ external transcribed spacer (5′ ETS). Moreover, the altered U3 snoRNA causes mRNA and protein differential expression in HCF or HPF cells. Conclusion: The atypical U3 snoRNA regulates the translation of specific proteins to exert a suppressive function in Pterygia through modulating the 18S RNA synthesis. Here, we uncover a novel insight into U3 snoRNA biology in the development of Pterygia.
Project description:Gene expression profile of acute myeloid leukemia. Bone marrow (BM) samples from 43 adult patients with newly de novo diagnosed AML.All samples contained more than 80% blast cells. Total RNA was extracted using Trizol reagent (Life Technologies, Gaithersburg, MD) and purified with RNeasy Mini Kit (Quiagen, Valencia, CA). The RNA integrity was assessed using Agilent 2100 Bioanalyzer (Agilent, Palo Alto, CA). The labeled RNA was then fragmented and hybridazed to HU-133A oligonucleotide array (Affymetrix, Santa Clara, CA), which contained 22,283 probe sets, according to Affymetrix protocols. The arrays were scanned using Gene Array Scanner (Affymetrix). Keywords = expression profile Keywords = myeloid leukemia Keywords = microarrays Keywords: other
Project description:Label-free quantitation dataset from 44 representative Acute Myeloid Leukemia (AML) patients from the LAML TCGA dataset, and 6 healthy bone marrow derived controls including 3 lineage-depleted and 3 CD34+ selected bone marrows.