Nucleosome structure and positioning play pivotal roles in gene regulation, DNA repair and other essential processes in eukaryotic cells. Nucleosomal DNA is thought to be uniformly inaccessible to DNA binding and processing factors, such as MNase. Here, we show, however, that nucleosome accessibility and sensitivity to MNase varies. Digestion of Drosophila chromatin with two distinct concentrations of MNase revealed two types of nucleosomes: sensitive and resistant. MNase-resistant nucleosome arrays are less accessible to low concentrations of MNase, whereas MNase-sensitive arrays are degraded by high concentrations. MNase-resistant nucleosomes assemble on sequences depleted of A/T and enriched in G/C containing dinucleotides. In contrast, MNase-sensitive nucleosomes form on A/T rich sequences represented by transcription start and termination sites, enhancers and DNase hypersensitive sites. Lowering of cell growth temperature to ~10°C stabilizes MNase-sensitive nucleosomes suggesting that variations in sensitivity to MNase are related to either thermal fluctuations in chromatin fiber or the activity of enzymatic machinery. In the vicinity of active genes and DNase hypersensitive sites nucleosomes are organized into synchronous, periodic arrays. These patterns are likely to be caused by “phasing” nucleosomes off a potential barrier formed by DNA-bound factors and we provide an extensive biophysical framework to explain this effect. Overall design: RNA-seq S2 cells Drosophila melanogaster
Genome-wide profiling of nucleosome sensitivity and chromatin accessibility in Drosophila melanogaster.
Specimen part, Subject
View SamplesHepatic cancer (HC), as one of the common malignancies in the world, is characterized by malignant cell prolifeHCion and growth, and hepatocarcinogenesis covers the stages of non-specific liver injury, liver fibrosis, liver cirrhosis, dysplasia nodules and finally liver carcinoma
Correlation between liver cancer occurrence and gene expression profiles in rat liver tissue.
Specimen part
View SamplesNonalcoholic fatty liver disease (NAFLD) is a common disorder characterized by excessive hepatic fat accumulation, and potentially resulting in non-alcoholic steatohepatitis (NASH), liver cirrhosis (LC) and end-stage liver disease
Correlation analysis between gene expression profile of rat liver tissues and high-fat emulsion-induced nonalcoholic fatty liver.
Specimen part
View SamplesRecently a genome of Russian individual (somatic DNA from blood) was sequenced (Skryabin et al. 2009). That study was continued to find a linkage between genetic differences in parental alleles and bias in biallelic expression of genes.
Individual genome sequencing identified a novel enhancer element in exon 7 of the CSFR1 gene by shift of expressed allele ratios.
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Quantitative trait loci affecting atherosclerosis at the aortic root identified in an intercross between DBA2J and 129S6 apolipoprotein E-null mice.
Sex, Specimen part
View SamplesStrain differences influence susceptibility to atherosclerosis. Apolipoprotein E-null mice on a DBA/2J genetic background (DBA-apoE) and C57BL/6 (B6-apoe) are highly susceptible to atherosclerosis in the aortic root area compared with those on a 129S6/SvEvTac background (129-apoE).
Quantitative trait loci affecting atherosclerosis at the aortic root identified in an intercross between DBA2J and 129S6 apolipoprotein E-null mice.
Sex, Specimen part
View SamplesPTEN loss or PI3K/AKT signaling pathway activation correlates with human prostate cancer progression and metastasis. However, in preclinical murine models, deletion of Pten alone fails to mimic the significant metastatic burden that frequently accompanies the end stage of human disease. To identify additional pathway alterations that cooperate with PTEN loss in prostate cancer progression, we surveyed human prostate cancer tissue microarrays and found that the RAS/MAPK pathway is significantly elevated both in primary and metastatic lesions. In an attempt to model this event, we crossed conditional activatable K-rasG12D/WT mice with the prostate conditional Pten deletion model we previously generated. Although RAS activation alone cannot initiate prostate cancer development, it significantly accelerated progression caused by PTEN loss, accompanied by epithelial-to-mesenchymal transition (EMT) and macrometastasis with 100% penitence. A novel stem/progenitor subpopulation with mesenchymal characteristics was isolated from the compound mutant prostates, which was highly metastatic upon orthotopic transplantation. Importantly, inhibition of RAS/MAPK signaling by PD325901, a MEK inhibitor, significantly reduced the metastatic progression initiated from transplanted stem/progenitor cells. Collectively, these data indicate that activation of RAS/MAPK signaling serves as a potentiating second hit to alteration of the PTEN/PI3K/AKT axis and co-targeting both pathways is highly effective in preventing the development of metastatic prostate cancers.
Pten loss and RAS/MAPK activation cooperate to promote EMT and metastasis initiated from prostate cancer stem/progenitor cells.
Specimen part
View SamplesStrain differences influence susceptibility to atherosclerosis. Apolipoprotein E-null mice on a DBA/2J genetic background (DBA-apoE) are highly susceptible to atherosclerosis in the aortic root area compared with those on a 129S6/SvEvTac background (129-apoE).
Quantitative trait loci affecting atherosclerosis at the aortic root identified in an intercross between DBA2J and 129S6 apolipoprotein E-null mice.
Sex, Specimen part
View SamplesStrain differences influence susceptibility to atherosclerosis. Apolipoprotein E-null mice on a C57BL/6 genetic background (B6-apoE) are highly susceptible to atherosclerosis in the aortic root area compared with those on a 129S6/SvEvTac background (129-apoE).
Quantitative trait loci affecting atherosclerosis at the aortic root identified in an intercross between DBA2J and 129S6 apolipoprotein E-null mice.
Sex, Specimen part
View SamplesTo understand how atypical bHLH, INCREASED LEAF INCLINATION1 (ILI1)-BINDING bHLH-1 (IBH1) (At2g43060), and close homologue, IBH1-like1 (IBL1) (At4g30410), interact to regulate cell elongation, genome-wide RNA-Seq expression analyses of IBH1 and IBL1 gain-(IBH1OE, IBL1OE) and loss-of-function (ibh1 (SALK 049177), ibl1(SALK 119457)) mutants were conducted. Overall design: For loss-of-function mutant, homozygous ibh1(SALK 049177) and ibl1(SALK 119457) were compared to wild type (Col). For gain-of-function mutant, homozygous 35Spro:IBH1-GFP and 35Spro:IBL1-GFP were compared to wild type (Col). Total RNAs were extactced from seedling of each genotypes. For each genotype two biological replicates were sequenced.
Helix-loop-helix/basic helix-loop-helix transcription factor network represses cell elongation in Arabidopsis through an apparent incoherent feed-forward loop.
Specimen part, Subject
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