Sir2 is an NAD+-dependent histone deacetylase, and is the founding member of a large, phylogentically conserved, family of such deacetylases called the Sirtuins. The budding yeast, Saccharomyces cerevisiae, harbors 4 paralogs of Sir2, known as Hst1, Hst2, Hst3, and Hst4. Reducing the intracellular NAD+ concentration is inhibitory for the Sirtuins, and raising the intracellular nicotinamide (NAM) concentration is inhibitory. Microarray gene expression analysis was used to identify novel classes of yeast genes whose expression is altered when either NAD+ concentration is reduced or NAM is elevated. A subset of genes involved in thiamine biosynthesis was identified as being upregulated when Sir2 or Hst1 was inactivated.
Thiamine biosynthesis in Saccharomyces cerevisiae is regulated by the NAD+-dependent histone deacetylase Hst1.
No sample metadata fields
View SamplesThe chronological lifespan (CLS) of Saccharomyces cerevisiae is defined as the number days that non-dividing cells remain viable, typically in stationary phase cultures or in water. CLS is extended by restricting glucose in the starting cultures, and is considered a form of caloric restriction (CR). Through a previous genetic screen our lab determined that deleting components of the de novo purine biosynthesis pathway also significantly increased CLS. Significant similarities in gene expression profiles between calorie restricted WT cells and a non-restricted ade4 mutant suggested the possibility of common gene expression biomarkers of all chronologically long lived cells that could also provide insights into general mechanisms of lifespan extension. We have identified additional growth conditions that extend CLS of WT cells, including supplementation of the media with isonicotinamide (INAM), a known sirtuin activator, or by supplementation with a concentrate collected from the expired media of a calorie restricted yeast culture, presumably due to an as yet unidentified longevity factor. Using these varied methods to extend CLS, we compared gene expression profiles in the aging cells (at day 8) to identify functionally relevant biomarkers of longevity. Nineteen genes were differentially regulated in all 4 of the long-lived populations relative to wild type. Of these 19 genes, viable haploid deletion mutants were available for 16 of them, and 12 were found to have a significant impact on CLS.
Functional genomic analysis reveals overlapping and distinct features of chronologically long-lived yeast populations.
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View SampleshTERT/cdk4 immortalized myogenic human cell lines represent an important tool for skeletal muscle research, being used as therapeutically-pertinent models of various neuromuscular disorders and in numerous fundamental studies of muscle cell function. However, the cell cycle is linked to other cellular processes such as integrin regulation, the PI3K/Akt pathway, and microtubule stability, raising the question as to whether transgenic modification of the cell cycle results in secondary effects that could undermine the validity of these cell models. Here we subjected healthy and disease lines to intensive transcriptomic analysis, comparing immortalized lines with their parent primary populations in both differentiated and undifferentiated states, and testing their myogenic character by comparison with non-myogenic (CD56-negative) cells. We found that immortalization has no measurable effect on the myogenic cascade or on any other cellular processes, and that it was protective against the systems level effects of senescence that are observed at higher division counts of primary cells.
Skeletal muscle characteristics are preserved in hTERT/cdk4 human myogenic cell lines.
Specimen part, Disease, Disease stage
View SamplesAcute Lymphoblastic Leukemia (ALL) in infants (<1 year) is characterized by a poor prognosis and a high incidence of MLL translocations. Several studies demonstrated the unique gene expression profile associated with MLL-rearranged ALL, but generally small cohorts were analyzed as uniform patient groups regardless of the type of MLL translocation, while the analysis of translocation-negative infant ALL remained unacknowledged.
Gene expression profiling-based dissection of MLL translocated and MLL germline acute lymphoblastic leukemia in infants.
Sex, Age, Specimen part
View SamplesAlthough the prognosis for childhood Acute Lymphoblastic Leukemia (ALL) in general has improved tremendously over the last decades, the survival chances for infants (<1 year of age) with ALL remains poor.
Association of high-level MCL-1 expression with in vitro and in vivo prednisone resistance in MLL-rearranged infant acute lymphoblastic leukemia.
Sex, Specimen part, Disease
View SamplesWe studied the KRAS and NRAS mutational status in pediatric MLL-AF4+ leukemia patients by means of ultra deep amplicon sequencing. The gene expression profiles of RAS wild type and RAS mutated patients were investigated by gene expression analysis. We showed that mutated patients were characterized by a RAS related expression signature.
Deciphering KRAS and NRAS mutated clone dynamics in MLL-AF4 paediatric leukaemia by ultra deep sequencing analysis.
Specimen part, Disease, Disease stage, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
High expression of miR-125b-2 and SNORD116 noncoding RNA clusters characterize ERG-related B cell precursor acute lymphoblastic leukemia.
Specimen part, Disease, Disease stage
View SamplesERG-related B cell precursor acute lymphoblastic leukemia (BCP ALL) is a recently described childhood ALL subtype characterized by aberrant ERG protein expression and highly recurrent ERG intragenic deletions. Several studies reported a remarkably favourable outcome for ERG-related BCP-ALL despite a high incidence of apparently inauspicious IKZF1 aberrations. In this study we investigated by integrative genomic analysis the main features of the ERG-related group in a cohort of B-others BCP ALL patients enrolled in the AIEOP ALL 2000 therapeutic protocol. We report a specific microRNA and snoRNA signature that characterizes ERG-related patients with up-regulation of the miR-125b-2 cluster on chromosome 21 and several snoRNAs in the Prader-Willi locus at 15q11.2, including the orphan SNORD116 cluster. Given the current lack of parameters for a comprehensive classification we suggest toexploit the noncoding RNAs signature for differential diagnosis of ERG-related patients.
High expression of miR-125b-2 and SNORD116 noncoding RNA clusters characterize ERG-related B cell precursor acute lymphoblastic leukemia.
Specimen part, Disease, Disease stage
View SamplesWhile genetic mutation is a hallmark of cancer, many cancers also acquire epigenetic alterations during tumorigenesis including aberrant DNA hypermethylation of tumor suppressors as well as changes in chromatin modifications as caused by genetic mutations of the chromatin-modifying machinery. However, the extent of epigenetic alterations in cancer cells has not been fully characterized. Here, we describe the first complete methylome maps at single nucleotide resolution of a low-passage breast cancer cell line and primary human mammary epithelial cells. We find widespread DNA hypomethylation in the cancer cell, primarily at partially methylated domains (PMDs) in normal breast cells. Unexpectedly, genes within these regions are largely silenced in cancer cells. The loss of DNA methylation in these regions is accompanied by formation of repressive chromatin, with a significant fraction displaying allelic DNA methylation where one allele is DNA methylated while the other allele is occupied by histone modifications H3K9me3 or H3K27me3. Our results show a mutually exclusive and complementary relationship between DNA methylation and H3K9me3 or H3K27me3. These results suggest that global DNA hypomethylation in breast cancer is tightly linked to the formation of repressive chromatin domains and gene silencing, thus identifying a potential epigenetic pathway for gene regulation in cancer cells and suggesting a possible new approach toward the development of cancer therapeutics. Overall design: mRNA-Seq of polyA-selected RNA from breast cancer HCC1954 and normal breast HMEC. 36 cycles of sequencing on Illumina platform.
Global DNA hypomethylation coupled to repressive chromatin domain formation and gene silencing in breast cancer.
No sample metadata fields
View SamplesGEP class prediction in association with CI-FISH (42 candidate genes) and patient MRD stratification
Linking genomic lesions with minimal residual disease improves prognostic stratification in children with T-cell acute lymphoblastic leukaemia.
Specimen part, Disease, Disease stage
View Samples