Project description:We found that the germline transcription factor double homeobox 4 (DUX4) is upregulated upon infection with wild-type herpes simplex virus-1 (HSV-1). The goal of this experiment was to compare the cellular transcriptome of HEK293T cells that were infected with HSV-1 (KOS strain), or transfected with a plasmid encoding human DUX4.
Project description:DUX4 is known to be crucial for TEs induction during zygotic genome activation in early embryonic development. In adults, DUX4 is usually silenced and we previously showed that DUX4 expression is induced by infection with various DNA viruses. We demonstrate binding of DUX4 to TEs upon herpesviral infection and analysis of genes adjacent to TEs shows pathways that are known to be crucial for tumor development. Overexpression of DUX4 significantly induced TEs expression, while its knockout (KO) diminished TEs expression upon HSV-1 infection, underscoring the essential role of DUX4 in TEs activation.
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.
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.
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.
Project description:Analysis of ex vivo isolated lymphatic endothelial cells from the dermis of patients to define type 2 diabetes-induced changes. Results preveal aberrant dermal lymphangiogenesis and provide insight into its role in the pathogenesis of persistent skin inflammation in type 2 diabetes. The ex vivo dLEC transcriptome reveals a dramatic influence of the T2D environment on multiple molecular and cellular processes, mirroring the phenotypic changes seen in T2D affected skin. The positively and negatively correlated dLEC transcripts directly cohere to prolonged inflammatory periods and reduced infectious resistance of patients´ skin. Further, lymphatic vessels might be involved in tissue remodeling processes during T2D induced skin alterations associated with impaired wound healing and altered dermal architecture. Hence, dermal lymphatic vessels might be directly associated with T2D disease promotion.
Project description:Differentiated NT2 cells are a potentially useful model system to study herpes simples virus (HSV) replication in human neurons. These cells can be irreversibly differentiated into NT-neurons in the presence of retinoic acid and non-dividing cultures NT-neurons can be maintained for up to several months without retinoic acid. HSV is capable of infecting and replicating in differentiated NT-neurons and thus differentiated NT-neurons provide a ready source of human post-mitotic cells which can be useful to study certain aspects of the interaction of HSV and the neuron. Microarray analysis was used to examine how HSV-1 infection modulates cellular transcription in human NT-neurons, focusing on changes that take place during the first 24 hours following infection and compared to changes resulting from infection with inactivated virus. In addition, the transcriptional changes resulting from virus infection of neurons were compared to those observed in primary human fibroblasts. At early times after HSV infection a small number of cellular transcripts in NT-Neurons appear to be increased in abundance. Most of these transcripts that are up-regulated after infection are not unique to neuronal cells, and possibly represent a common cellular response to HSV infection. A few transcripts were not detected in infected human fibroblasts and may represent part of a transcriptional profile specific to this type of human neuronal cell. In contrast to the situation at early times after infection, analysis of cellular transcripts in NT-neurons at late times after infection is complicated by the overall profound decrease in cellular transcription. Thus, microarray analysis appeared to be most useful as a screening method for transcription changes following infection at early times after virus infection of NT-neurons. Two-condition experiment, HSV-1 infected versus uninfected NTNeurons, 4 independent biological replicate sets (uninfected/infected) in dual channel array setup (Cy3/Cy5).