Autophagy as a conserved degradation and recycling machinery is important in normal development and physiology, and defects in this process are linked to many kinds of disease. Because too much or too little autophagy can be detrimental, the process must be tightly regulated both temporally and in magnitude. The transcriptional induction and repression of the autophagy-related (ATG) genes is one crucial aspect of this regulation, but the transcriptional regulators that modulate autophagy are not well characterized. In this study, we identified Pho23 as a master transcriptional repressor for autophagy, with transcriptome profiling revealing that ATG9 is one of the key target genes. Physiological studies with a PHO23 null mutant, or with strains expressing modulated levels of Atg9, demonstrate a critical role of this protein as a regulator of autophagosome formation frequency; Atg9 protein levels correlate with the number of autophagosomes generated upon autophagy induction, and the level of autophagy activity. Overall design: WT yeast and pho23 deletion mutants were grown under nutrient rich or nitrogen starvation conditions; gene expression was quantified across these 4 samples.
Transcriptional regulation by Pho23 modulates the frequency of autophagosome formation.
Subject
View SamplesProtein-RNA interactions are integral components of nearly every aspect of biology including regulation of gene expression, assembly of cellular architectures, and pathogenesis of human diseases. However, studies in the past few decades have only uncovered a small fraction of the vast landscape of the protein-RNA interactome in any organism, and even less is known about the dynamics of protein-RNA interactions under changing developmental and environmental conditions. Here, we describe the gPAR-CLIP (global photoactivatable-ribonucleoside-enhanced crosslinking and immunopurification) approach for capturing regions of the transcriptome bound by RNA-binding proteins (RBPs) in budding yeast. We report over 13,000 RBP crosslinking sites in untranslated regions (UTR) covering 72% of protein-coding transcripts encoded in the genome, confirming 3' UTRs as major sites for RBP interaction. Comparative genomic analyses reveal that RBP crosslinking sites are highly conserved, and RNA folding predictions indicate that secondary structural elements are constrained by protein binding and may serve as generalizable modes of RNA recognition. Finally, 38% of 3' UTR crosslinking sites show changes in RBP occupancy upon glucose or nitrogen deprivation, with major impacts on metabolic pathways as well as mitochondrial and ribosomal gene expression. Our study offers an unprecedented view of the pervasiveness and dynamics of protein-RNA interactions in vivo. Overall design: Duplicate gPAR-CLIP and mRNA-seq libraries were sequenced from yeast strains for each of three conditions: log-phase growth, growth after 2 hour glucose starvation, and growth after 2 hour nitrogen starvation. Additional duplicate mRNA-seq libraries were sequenced from yeast strains grown in the absence of 4-thiouracil. gPAR-CLIP libraries were used to determine regions of mRNA bound by proteins. mRNA-seq libraries served as controls for mRNA abundance. A Puf3p PAR-CLIP library was sequenced to determine how well gPAR-CLIP captured the binding signatures of a single RNA-binding protein.
RNA promotes phase separation of glycolysis enzymes into yeast G bodies in hypoxia.
Cell line, Treatment, Subject
View SamplesWe and others have previously shown that glomerular endothelial cells and podocytes express hypoxia-inducible transcription factors (HIFs). HIFs bind to hypoxia response elements in target genes, such as vascular endothelial growth factor, which is continually produced by podocytes throughout life. To further assess function of HIFs in podocyte biology, podocin-Cre mice were mated with floxed von Hippel-Lindau (VHL) mice to selectively delete VHL, a component of an E3 ligase complex responsible for degradation of HIFs in normoxia.
Deletion of von Hippel-Lindau in glomerular podocytes results in glomerular basement membrane thickening, ectopic subepithelial deposition of collagen {alpha}1{alpha}2{alpha}1(IV), expression of neuroglobin, and proteinuria.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Human oocytes reprogram somatic cells to a pluripotent state.
Specimen part
View SamplesThe exchange of the oocyte's genome with the genome of a somatic cell, followed by the derivation of pluripotent stem cells, could enable the generation of specific cell types affected in degenerative human diseases. Such cells, carrying the patient's genome, might be useful for cell replacement. Here we report that the development of human oocytes activated after genome exchange invariably arrests at the late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, they efficiently develop to the blastocyst stage. Human stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies the removal of the oocyte genome as the primary cause of developmental failure after genome exchange. Future work should focus on the critical elements that are associated with the human oocyte genome.
Human oocytes reprogram somatic cells to a pluripotent state.
Specimen part
View SamplesThe exchange of the oocytes genome with the genome of a somatic cell, followed by the derivation of pluripotent stem cells, could enable the generation of specific cell types affected in degenerative human diseases. Such cells, carrying the patients genome, might be useful for cell replacement. Here we report that the development of human oocytes activated after genome exchange invariably arrests at the late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, they efficiently develop to the blastocyst stage. Human stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies the removal of the oocyte genome as the primary cause of developmental failure after genome exchange. Future work should focus on the critical elements that are associated with the human oocyte genome.
Human oocytes reprogram somatic cells to a pluripotent state.
Specimen part
View SamplesWe characterized the gene expression by Hierarchical Clustering and one-matrix clustering in hESC, day 12 progenitors, day 25-day 27, day82 differentiated hypothalamic neurons from hESCs and day 45 neurons derived from iPSCs generated from controls (2 independent) and BBS (Bardet-Biedl Syndrome, 3 independent) subjects. Overall design: RNA was isolated from cells of 13 samples (1 hESC, triplicate for day 12 progenitors, 1 day 25 neuron sample, duplicate for day 27 neuron samples, 1 day 82 neuron sample, five day 45 neuron samples made from 5 independent iPSC lines ) using RNeasy Micro Kit (QIAGEN). Quality control of the RNA was carried out with the Agilent Bio-analyzer, Qubit 2.0 at the MPSR of Columbia University. 100 ng of RNA with RIN = 9 were used for generating mRNA-focused libraries using TruSeq RNA Sample Preparation Kit v2 and sequencing on an Illumina 2000/2500 V3 Instrument offered by the Columbia Genome Center.
Differentiation of hypothalamic-like neurons from human pluripotent stem cells.
No sample metadata fields
View SamplesThe transfer of somatic cell nuclei into oocytes can give rise to pluripotent stem cells, holding promise for autologous cell replacement therapy. Though reprogramming of somatic cells by nuclear transfer was first demonstrated more than 60 years ago, only recently have human diploid embryonic stem cells been derived after nuclear transfer of fetal and neonatal fibroblasts. Because of the therapeutic potential of developing diploid embryonic stem cell lines from adult cells of normal and diseased human subjects, we have systematically investigated the parameters affecting efficiency and developmental potential in their derivation. We found that improvements to the oocyte activation protocol, including the use of both a kinase and a translation inhibitor, and cell culture in the presence of histone deacetylase inhibitors enable development of diploid cells to the blastocyst stage. Developmental efficiency varied significantly between oocyte donors, and was inversely related to the number of days of hormonal stimulation required to reach mature oocytes, while the daily dose of gonadotropin or the total number of MII oocytes retrieved did not affect developmental outcome. The use of diluted Sendai virus in calcium-free medium during nuclear transfer improved developmental potential, while the use of concentrated Sendai virus induced an increase in intracellular calcium and caused premature oocyte activation. Using these modifications to the nuclear transfer protocol, we successfully derived diploid pluripotent stem cell lines from both postnatal and adult somatic cells of a type 1 diabetic subject.
Human oocytes reprogram adult somatic nuclei of a type 1 diabetic to diploid pluripotent stem cells.
Sex, Specimen part, Cell line
View SamplesThe CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein in heart, we performed RNA-Seq of polyA+ RNA from mice inducibly expressing Celf1 in the heart. Overall design: Mice were engineered to express the reverse tetracycline trans-activator (rtTA) from a heart-specific alpha myosin heavy chain promoter, and an N-terminal Flag-tagged version of the LYLQ isoform of human Celf1 from a tet-inducible promoter. Mice were fed doxycycline to induce Celf1 expression in heart, and hearts were harvested from 3 mice each at 12 hour, 24 hour, 72 hour, and 7 day time points. To account for potential doxycycline-dependent effects, control mice were fed doxycycline for 72 hours but these mice did not contain the tet-inducible Celf1 cassette. In total, 15 hearts were analyzed by RNA-Seq.
Antagonistic regulation of mRNA expression and splicing by CELF and MBNL proteins.
No sample metadata fields
View SamplesThe CUG-BP and ETR-3-like factor 1 (Celf1) RNA binding protein plays an important role in heart and muscle development, and is over-expressed in the disease myotonic dystrophy. Celf1 has known roles in regulation of RNA splicing, RNA stability, and protein translation. To identify transcriptome-wide targets of the Celf1 protein in heart, we performed RNA-Seq of polyA+ RNA from mice inducibly expressing Celf1 in the muscle. Overall design: Mice were engineered to express the reverse tetracycline trans-activator (rtTA2S-M2) from the rate myosin light chain 1/3 promoter/enhancer, and an N-terminal Flag-tagged version of the LYLQ isoform of human Celf1 from a tet-inducible promoter. Mice were fed doxycycline to induce Celf1 expression in muscle, and gastrocnemius muscles were harvested from 3 mice each at 12 hour, 24 hour, 72 hour, and 7 day time points. To account for potential doxycycline-dependent effects, control mice were fed doxycycline for 72 hours but these mice did not contain the tet-inducible Celf1 cassette. In total, 15 gastrocnemius samples were analyzed by RNA-Seq.
Antagonistic regulation of mRNA expression and splicing by CELF and MBNL proteins.
No sample metadata fields
View Samples