Large numbers of ribonucleotides are incorporated into the eukaryotic nuclear genome during S-phase due to imperfect discrimination against ribonucleoside triphosphates by the replicative DNA polymerases. Ribonucleotides, by far the most common DNA lesion in replicating cells, destabilize the DNA, and an evolutionarily conserved DNA repair machinery, ribonucleotide excision repair (RER), ensures ribonucleotide removal. Complete lack of RER is embryonically lethal. Partial loss-of-function mutations in the genes encoding subunits of RNase H2, the enzyme essential for initiation of RER, cause the SLE-related type I interferonopathy Aicardi-Goutières syndrome. Here we establish that selective inactivation of RER in mouse epidermis results in spontaneous DNA damage, epidermal hyperproliferation associated with loss of hair follicle stem cells and hair follicle function. The animals develop keratinocyte intraepithelial neoplasia and invasive squamous cell carcinoma with complete penetrance, despite potent type I interferon production and skin inflammation. Compromised RER-mediated genome maintenance might represent an important tumor-promoting principle in human cancer. Overall design: CD45+ CD49f- cells were were isolated from skin cell suspensions by FACS. Total RNA was isolated using the RNeasy Micro Kit+ (Qiagen). mRNA libraries were prepared using a SMART protocol and subjected to deep sequencing on an Illumina®HiSeq 2500.
Ribonucleotide Excision Repair Is Essential to Prevent Squamous Cell Carcinoma of the Skin.
Specimen part, Subject
View SamplesLarge numbers of ribonucleotides are incorporated into the eukaryotic nuclear genome during S-phase due to imperfect discrimination against ribonucleoside triphosphates by the replicative DNA polymerases. Ribonucleotides, by far the most common DNA lesion in replicating cells, destabilize the DNA, and an evolutionarily conserved DNA repair machinery, ribonucleotide excision repair (RER), ensures ribonucleotide removal. Complete lack of RER is embryonically lethal. Partial loss-of-function mutations in the genes encoding subunits of RNase H2, the enzyme essential for initiation of RER, cause the SLE-related type I interferonopathy Aicardi-Goutières syndrome. Here we establish that selective inactivation of RER in mouse epidermis results in spontaneous DNA damage, epidermal hyperproliferation associated with loss of hair follicle stem cells and hair follicle function. The animals develop keratinocyte intraepithelial neoplasia and invasive squamous cell carcinoma with complete penetrance, despite potent type I interferon production and skin inflammation. Compromised RER-mediated genome maintenance might represent an important tumor-promoting principle in human cancer. Overall design: Keratinocytes (CD49f+) cells were isolated from skin cell suspensions by FACS. Total RNA was isolated using the RNeasy Mini Kit+ (Qiagen). mRNA libraries were prepared and subjected to deep sequencing on an Illumina®HiSeq.
Ribonucleotide Excision Repair Is Essential to Prevent Squamous Cell Carcinoma of the Skin.
Specimen part, Subject
View SamplesDNA is strictly compartmentalised within the nucleus to prevent autoimmunity despite this cGAS, a cytosolic sensor of dsDNA, is activated in autoinflammatory disorders and by DNA damage. Precisely how cellular DNA gains access to the cytoplasm remains to be determined. Here, we report that cGAS localises to micronuclei arising from genome instability in a model of monogenic autoinflammation, after exogenous DNA damage and spontaneously in human cancer cells. These micronuclei occur after mis-segregation of DNA during cell division and consist of chromatin surrounded by their own nuclear membrane. Breakdown of the micronuclear envelope, a process associated with chromothripsis, leads to rapid accumulation of cGAS, providing a mechanism by which self-DNA becomes exposed to the cytosol. cGAS binds to and is activated by chromatin and consistent with a mitotic origin, micronuclei formation and the proinflammatory response following DNA-damage are cell-cycle dependent. Furthermore, by combining live-cell laser microdissection with single cell transcriptomics, we establish that induction of interferon stimulated gene expression occurs in micronucleated cells. We therefore conclude that micronuclei represent an important source of immunostimulatory DNA. As micronuclei formed from lagging chromosomes also activate this pathway, cGAS recognition of micronuclei may act as a cell-intrinsic immune surveillance mechanism detecting a range of neoplasia-inducing processes. Overall design: RNA-seq of 35 individual mouse embryonic fibroblasts 48 h after 1 Gy irradiation: 21 test (with micronuclei) and 14 controls (without micronuclei).
cGAS surveillance of micronuclei links genome instability to innate immunity.
Specimen part, Cell line, Treatment, Subject
View SamplesThe v-erbA oncogene belongs to a superfamily of transcription factors called nuclear receptors, which includes the retinoic acid receptors (RARs) responsible for mediating the effects of retinoic acid (RA). Nuclear receptors bind to specific DNA sequences in the promoter region of target genes and v-erbA is known to exert a dominant negative effect on the activity of the RARs. The repressor activity of v-erbA has been linked to the development of hepatocellular carcinoma (HCC) in a mouse model. We have used microarray analysis to identify genes differentially expressed in hepatocytes in culture (AML12 cells) stably transfected with v-erbA and exposed to RA. We have found that v-erbA can affect expression of RA-responsive genes. We have also identified a number of v-erbA-responsive genes that are known to be involved in carcinogenesis and which may play a role in the development of HCC.
Modulation of expression of RA-regulated genes by the oncoprotein v-erbA.
Specimen part, Cell line
View SamplesTranscription factors that regulate quiescence, proliferation, and homing of lymphocytes are critical for effective immune system function. In the present study, we demonstrated that the transcription factor ELF4 directly activates the tumor suppressor KLF4 downstream of T cell receptor (TCR) signaling to induce cell cycle arrest in nave CD8+ T cells. Elf4- and Klf4-deficient mice accumulated CD8+CD44hi T cells during steady-state conditions and generated more memory T cells after immunization. The homeostatic expansion of CD8+CD44hi T cells in Elf4-null mice resulted in a redistribution of cells to non-lymphoid tissue due to reduced expression of the transcription factor KLF2, and the surface proteins CCR7 and CD62L. This work describes the combinatorial role of lymphocyte-intrinsic factors in the control of T cell homeostasis, activation and homing.
Transcription factor ELF4 controls the proliferation and homing of CD8+ T cells via the Krüppel-like factors KLF4 and KLF2.
Specimen part
View SamplesEpilepsy is a common cause of morbidity affecting approximately one third of patients with primary brain tumors. However, the molecular mechanism underlying the tumor induced epileptogenesis is poorly understood. The alteration in peritumoral microenvironments is believed to play a significant role in inducing epileptogenesis.
Transcriptomic profiling of human peritumoral neocortex tissues revealed genes possibly involved in tumor-induced epilepsy.
Sex, Specimen part, Disease, Disease stage
View SamplesM端ller cells (MCs) play a crucial role in the retina, and cultured MC lines are an important tool with which to study MC function. Transformed MC lines have been widely used; however, the transformation process can also lead to unwanted changes compared to the primary cells from which they were derived. A monoclonal spontaneously immortalized rat M端ller cell line, SIRMu-1, was derived from primary rat MCs and characterized by RNA-sequencing (in addition to immunofluorescence and western blotting) in comparison to primary MCs and the SV40-immortalized MC line, rMC-1. Overall design: RNA-seq was performed on enriched polyA RNA from primary M端ller cells (4 biological replicates of passage numbers 3-4), SIRMu-1 cells (5 biological replicates of passage numbers 6-20, two of which were cultured in the presence of the antibiotic gentamicin and the antifungal amphotericin B to match the culture conditions of the primary MCs), and rMC-1 cells (3 biological replicates of passage numbers 23-26).
RNA sequencing data of cultured primary rat Müller cells, the spontaneously immortalized rat Müller cell line, SIRMu-1, and the SV40-transformed rat Müller cell line, rMC-1.
Specimen part, Cell line, Subject
View SamplesLoss of muscle mass occurs in a variety of diseases including cancer, chronic heart failure, AIDS, diabetes and renal failure, often aggravating pathological progression. Preventing muscle wasting by promoting muscle growth has been proposed as a possible therapeutic approach. Myostatin is an important negative modulator of muscle growth during myogenesis and myostatin inhibitors are attractive drug targets. However, the role of the myostatin pathway in adulthood and the transcription factors involved in the signaling are unclear. Moreover recent results confirm that other TGF members control muscle mass. Using genetic tools we perturbed this pathway in adult myofibers, in vivo, to characterize the downstream targets and their ability to control muscle mass. Smad2 and Smad3 are the transcription factors downstream of myostatin/TGF and induce an atrophy program which is MuRF1 independent and requires FoxO activity. Furthermore Smad2/3 inhibition promotes muscle hypertrophy independent of satellite cells but partially dependent of mTOR signalling. Thus myostatin and Akt pathways cross-talk at different levels. These findings point to myostatin inhibitors as good drugs to promote muscle growth during rehabilitation especially when they are combined with IGF1-Akt activators.
Smad2 and 3 transcription factors control muscle mass in adulthood.
Specimen part, Time
View SamplesB cell CLL/lymphoma 11A (BCL11A) is a transcription factor and regulator of hemoglobin switching that has emerged as a promising therapeutic target for sickle cell disease and thalassemia. In the hematopoietic system, BCL11A is required for B lymphopoiesis, yet its role in other hematopoietic cells, especially hematopoietic stem cells (HSCs) remains elusive. The extensive expression of BCL11A in hematopoiesis implicates context-dependent roles, highlighting the importance of fully characterizing its function as part of ongoing efforts for stem cell therapy and regenerative medicine. Here, we demonstrate that BCL11A is indispensable for normal HSC function. Bcl11a deficiency results in HSC defects, typically observed in the aging hematopoietic system. We find that downregulation of cyclin-dependent kinase 6 (Cdk6), and the ensuing cell-cycle delay, correlate with HSC dysfunction. Our studies define a mechanism for BCL11A in regulation of HSC function and have important implications for the design of therapeutic approaches to targeting BCL11A.
Bcl11a Deficiency Leads to Hematopoietic Stem Cell Defects with an Aging-like Phenotype.
Specimen part
View SamplesCHD4 is an ATPase able to use the energy from ATP to shift or remove nucleosomes from specific sites in the chromatin, thereby affecting accessability of gene regulatory elements. It is part of the NuRD complex.
Helicase CHD4 is an epigenetic coregulator of PAX3-FOXO1 in alveolar rhabdomyosarcoma.
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