Homo sapiens
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ABSTRACT:
PROVIDER: PRJNA269617 | ENA |
REPOSITORIES: ENA
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Project description:We demonstrate that the catalytic subunit of Polycomb Repressive Complex 2, EZH2, is targeted by the MELK-FOXM1 complex, which in turn promotes resistance to radiation in GSCs. Clinically, EZH2 and MELK are co-expressed in GBM and significantly induced in post-irradiation recurrent tumors whose expression inversely correlated with patient prognosis. Through gain-and loss-of-function study, our data show that MELK or FOXM1 contributes on GSC radioresistance by regulation of EZH2. We used microarrays to validate EZH2 target gene expression. GSCs were treated with shNT (control), shMELK, shFOXM1, and EZH2 overexpression. Total RNA was isolated using the Qiagen RNeasy kit (Qiagen).
2015-04-16 | E-GEOD-63963 | biostudies-arrayexpress
Project description:Glioblastoma progression and recurrence are suggested to be derived by glioblastoma stem-like cells (GSCs). There is limited knowledge about the expression and therapy response of LGR5 in GSCs. We have investigated the role of LGR5 in glioblastoma by knocking down LGR5 using short hairpin RNA targeting LGR5 mRNA (shLGR5) and non-target RNA (shNT) as control.
2018-10-18 | GSE109867 | GEO
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
| S-EPMC2531291 | biostudies-literature
Project description:In order to investigate the crucial role of PFKFB4 in glioblastoma stem-like cell (GSC) survival, gene expression microarray-based transcriptome analysis was conducted on GSCs transduced for 4 days with PFKFB4 shRNA compared with GSCs transduced with shNT.
2019-01-05 | GSE108742 | GEO
Project description:In order to investigate the crucial role of PRKCI in glioblastoma stem-like cell (GSC) survival, gene expression microarray-based transcriptome analysis was conducted on GSCs transduced for 4 days with PRKCI shRNA compared with GSCs transduced with shNT.
2016-01-21 | GSE77030 | GEO
Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.
2019-07-31 | GSE114179 | GEO
Project description:We report that these features are associated with distinct transcriptional programs, with vascular regions showing a proneural profile and hypoxic regions a mesenchymal pattern. As these regions harbor glioma stem cells (GSCs), we investigated the epigenetic regulation of these two niches. Proneural, perivascular GSCs activated EZH2, whereas mesenchymal GSCs in hypoxic regions expressed BMI1 protein. To determine the differential regional activation of EZH2 and BMI1 function, we performed chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) with H3K27me3 (histone modification by EZH2) or H2AK119Ub (histone modification by BMI1) antibodies in CD15-postive GSCs from enhancing and necrotic regions of two GBM specimens, and found over 80% of regional specific target genes displayed distinct H3K27me3 or H2AK119Ub marks, indicating distinct PRC function in GSCs residing in different regions. H3K27me3, generally associated with inhibition of transcription, marked neuronal and cellular development targets in both the enhancing and necrotic regions, albeit without substantial overlap in gene identity, with EZH2/SUZ12/H3K27me3 targets most significantly in the enhancing regions. In contrast, H2AK119Ub marked very different targets in the enhancing and necrotic regions, with H2AK119Ub in CD15-positive GSCs from the hypoxia (necrotic) regions marking genes strongly associated with mesenchymal subtype signaling pathways, such as TGFb, NFkB, and WNT, indicating probable microenvironment-specific functions of EZH2 and BMI1.
2017-10-01 | GSE103274 | GEO
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
| S-EPMC4686780 | biostudies-literature
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.
| S-EPMC3743458 | biostudies-literature