Homo sapiens
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PROVIDER: PRJNA146441 | ENA |
REPOSITORIES: ENA
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Project description:The cell surface receptor, Epithelial Cell Adhesion Molecule (EpCAM), is overexpressed in a variety of cancers and has been carefully examined for its functional role in carcinogenesis and its potential as a therapeutic target. However, little is known about the upstream molecular pathways that regulate EpCAM expression. To elucidate the mechanisms by which EpCAM expression is controlled, we designed a combinatorial screening strategy that utilized pooled shRNA gene knockdown with magnetically-activated cell separation for selection of cells with reduced EpCAM protein expression on the cell surface. The pooled RNAi screen was analyzed by comparing EpCAM-enriched and EpCAM-depleted cell populations for shRNA abundance using competitive hybridization to microarrays. Our RNAi screen and further validation efforts revealed that at least four genes (GRM1, SLITRK5, EFNA5, and IL23A) are important for EpCAM expression in the ovarian cancer cell line OVCAR8. Further investigations into the ephrin ligand, EFNA5, suggest that its activation by the Eph receptor, EPHA4, contributes to the regulation of EpCAM expression via a reverse signaling mechanism. Our screening strategy revealed novel mechanisms for the regulation of EpCAM expression and provides insight into the biology of this cancer-associated gene. Importantly, this study also demonstrates the utility of pooled RNAi screening in the identification of genes required for the regulation of cell surface protein expression.
2011-12-01 | GSE32985 | GEO
Project description:The cell surface receptor, Epithelial Cell Adhesion Molecule (EpCAM), is overexpressed in a variety of cancers and has been carefully examined for its functional role in carcinogenesis and its potential as a therapeutic target. However, little is known about the upstream molecular pathways that regulate EpCAM expression. To elucidate the mechanisms by which EpCAM expression is controlled, we designed a combinatorial screening strategy that utilized pooled shRNA gene knockdown with magnetically-activated cell separation for selection of cells with reduced EpCAM protein expression on the cell surface. The pooled RNAi screen was analyzed by comparing EpCAM-enriched and EpCAM-depleted cell populations for shRNA abundance using competitive hybridization to microarrays. Our RNAi screen and further validation efforts revealed that at least four genes (GRM1, SLITRK5, EFNA5, and IL23A) are important for EpCAM expression in the ovarian cancer cell line OVCAR8. Further investigations into the ephrin ligand, EFNA5, suggest that its activation by the Eph receptor, EPHA4, contributes to the regulation of EpCAM expression via a reverse signaling mechanism. Our screening strategy revealed novel mechanisms for the regulation of EpCAM expression and provides insight into the biology of this cancer-associated gene. Importantly, this study also demonstrates the utility of pooled RNAi screening in the identification of genes required for the regulation of cell surface protein expression. Two condition experiment; EpCAM-Bound or EpCAM-Unbound OVCAR8 cells vs Reference population of transduced cells without phenotypic selection; biological triplicate
2011-12-01 | E-GEOD-32985 | biostudies-arrayexpress
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:High throughput expression-based phenotyping and RNAi screening reveals novel regulators of planarian stem cells
| PRJNA874081 | ENA
Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.
2019-07-31 | GSE114179 | GEO
Project description:Endotype reversal as a novel strategy for screening drugs targeting familial Alzheimer's disease
| PRJNA377888 | ENA
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
Project description:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.
2023-01-08 | GSE154227 | GEO
Project description:Cortical thickness has been investigated since the beginning of the 20th century, but we do not know how similar the cortical thickness profiles among humans are. In this study, the local similarity of cortical thickness profiles was investigated using sliding window methods. Here, we show that approximately 5% of the cortical thickness profiles are similarly expressed among humans while 45% of the cortical thickness profiles show a high level of heterogeneity. Therefore, heterogeneity is the rule, not the exception. Cortical thickness profiles of somatosensory homunculi and the anterior insula are consistent among humans, while the cortical thickness profiles of the motor homunculus are more variable. Cortical thickness profiles of homunculi that code for muscle position and skin stimulation are highly similar among humans despite large differences in sex, education, and age. This finding suggests that the structure of these cortices remains well preserved over a lifetime. Our observations possibly relativize opinions on cortical plasticity.
| S-EPMC5738339 | biostudies-literature