Project description:Nucleolar ribosomal DNA (rDNA) repeats control ribosome manufacturing. rDNA harbors a ribosomal RNA (rRNA) gene and an intergenic spacer (IGS). RNA polymerase (Pol) I transcribes rRNA genes yielding the rRNA components of ribosomes. Pol II at the IGS induces rRNA production by preventing Pol I from excessively synthesizing IGS non-coding RNAs (ncRNAs) that can disrupt nucleoli. At the IGS, Pol II regulatory processes and whether Pol I function can be beneficial remain unknown. Here, we identify IGS Pol II regulators, uncovering nucleolar optimization via IGS Pol I. Compartment-enriched proximity-dependent biotin identification (compBioID) showed enrichment of the TATA-less promoter-binding TBPL1 and transcription regulator PAF1 with IGS Pol II. TBPL1 localizes to TCT motifs, driving Pol II and Pol I and maintaining its baseline ncRNA levels. PAF1 promotes Pol II elongation, preventing unscheduled R-loops that hyper-restrain IGS Pol I and its ncRNAs. PAF1 or TBPL1 deficiency disrupts nucleolar organization and rRNA biogenesis. In PAF1-deficient cells, repressing unscheduled IGS R-loops rescues nucleolar organization and rRNA production. Depleting IGS Pol I-dependent ncRNAs is sufficient to compromise nucleoli. We present the interactome of nucleolar Pol II and show its control by TBPL1 and PAF1 ensures IGS Pol I ncRNAs maintaining nucleolar structure and operation.
Project description:Introduction: The EORTC22033-26033 clinical trial investigated whether initial temozolomide (TMZ) chemotherapy confers survival advantage compared to radiotherapy (RT) in low grade glioma patients. In this study we performed gene expression profiling on tissues from this trial in order to identify markers associated with progression free survival and treatment response in this well-defined cohort of patients. Methods: Gene expression profiling, performed on 195 samples, was used to assign tumors to one of six intrinsic glioma subtypes (IGS; molecularly similar tumors predefined by unsupervised gene expression analysis) and to extract the cellular composition of immune infiltrates. DNA copy number changes were determined on samples assigned to IGS-16. Results: We confirm that IGS-subtypes are prognostic in EORTC22033-26033 clinical trial samples. Specific genetic changes segregate in distinct IGS subtypes: most samples assigned to IGS-9 have IDH-mutations combined with 1p19q codeletion, samples assigned to IGS-17 have IDH-mutations with intact 1p19q chromosomal arms and samples assigned to other intrinsic subtypes often are IDH-wildtype and 1p19q intact. A trend towards benefit from RT compared to TMZ was observed for samples assigned to IGS-9 (HR for TMZ is 1.90, 95% CI [0.95, 3.80], P=0.065), but not for samples assigned to IGS-17 (HR for TMZ vs RT is 0.87, 95% CI[0.50, 1.51], P=0.62). We did not identify genes significantly associated with progression free survival (PFS) within intrinsic subtypes, though follow-up time is limited. We also show that LGGs and GBMs differ in their immune-infiltrate with LGGs having higher suppressor and lower effector cell populations compared to GBMs. This suggests that LGGs are less amenable to checkpoint inhibitor type immune therapies than GBMs. Gene expression analysis and copy number analysis also identified one patient with a pilocytic astrocytoma (PA). Conclusion: Intrinsic glioma subtypes are prognostic for PFS in EORTC22033-26033 clinical trial samples.
Project description:Inoculation of endophyte-free (E-) Theobroma cacao leaves with Colletotrichum tropicale (E+), the dominant foliar fungal endophyte in healthy T. cacao, induced significant changes in the expression of hundreds of host genes. Further, E+ leaves exhibit enhanced pathogen resistance, increased lignin and cellulose content, reduced maximum rates of photosynthesis (Amax), and enrichment of nitrogen-15 and carbon-13 isotopes that all correspond to the changes in expression of specific functional genes in related pathways. Moreover, a cacao gene highly up-regulated in E+ leaves increases pathogen resistance apart from any direct endophyte effects. Thus, benefits of increased pathogen resistance in E+ plants are partially due to enhanced induction of intrinsic host defense pathways, and potential costs include reduced photosynthetic capacity and endophyte metabolism of host tissues. Similar effects are likely to be properties of most plant-endophyte interactions, suggesting general relevance to the design and interpretation of studies of genetic and phenotypic expression in plants. The objective of this experiment was to identify Theobroma cacao genes that are differentially expressed between leaves inoculated with fungal endophyte Colletotrichum tropicale (E+ leaves) and control un-inoculated leaves (E- leaves) 3 days post endophyte inoculation. The experiment was conducted in a Percival growth chamber (model I35LL, 115 volts, 1/4 Hp, series: 8503122.16, Percival Scientific, Inc., Perry IA) with 12/12 h light/dark photoperiod and temperatures of 30M-BM-:C and 26M-BM-:C respectively. Inoculation was done by aspersion of endophyte spores (2X10^6 spore/ml) to a group of T. cacao seedlings and a second group of seedlings were maintained as control un-inoculated (E- leaves). Then three biological replicates (each one consisting of one leaf from different plants) per treatment E+ and four leaves per treatment E- leaves) were collected and processed for a two color oligo microarray analysis.
Project description:Inoculation of endophyte-free (E-) Theobroma cacao leaves with Colletotrichum tropicale (E+), the dominant foliar fungal endophyte in healthy T. cacao, induced significant changes in the expression of hundreds of host genes. Further, E+ leaves exhibit enhanced pathogen resistance, increased lignin and cellulose content, reduced maximum rates of photosynthesis (Amax), and enrichment of nitrogen-15 and carbon-13 isotopes that all correspond to the changes in expression of specific functional genes in related pathways. Moreover, a cacao gene highly up-regulated in E+ leaves increases pathogen resistance apart from any direct endophyte effects. Thus, benefits of increased pathogen resistance in E+ plants are partially due to enhanced induction of intrinsic host defense pathways, and potential costs include reduced photosynthetic capacity and endophyte metabolism of host tissues. Similar effects are likely to be properties of most plant-endophyte interactions, suggesting general relevance to the design and interpretation of studies of genetic and phenotypic expression in plants.
Project description:Inoculation of endophyte-free (E-) Theobroma cacao leaves with Colletotrichum tropicale (E+), the dominant foliar fungal endophyte in healthy T. cacao, induced significant changes in the expression of hundreds of host genes. Further, E+ leaves exhibit enhanced pathogen resistance, increased lignin and cellulose content, reduced maximum rates of photosynthesis (Amax), and enrichment of nitrogen-15 and carbon-13 isotopes that all correspond to the changes in expression of specific functional genes in related pathways. Moreover, a cacao gene highly up-regulated in E+ leaves increases pathogen resistance apart from any direct endophyte effects. Thus, benefits of increased pathogen resistance in E+ plants are partially due to enhanced induction of intrinsic host defense pathways, and potential costs include reduced photosynthetic capacity and endophyte metabolism of host tissues. Similar effects are likely to be properties of most plant-endophyte interactions, suggesting general relevance to the design and interpretation of studies of genetic and phenotypic expression in plants.