Project description:Gene expression profiling was significantly different between der(1;7)(q10;p10) and -7/7q- patients by cluster analysis. There were total 1628 dysregulated genes in both der(1;7)(q10;p10) and -7/del(7q) cohorts.
Project description:The unbalanced translocation t(1;7)(q10;p10), generating 1q trisomy and 7q monosomy, is due to centromere-centromere juxtaposition. This dicentric chromosome is a recurrent change in myelodysplastic syndromes (MDS), with half the cases arising after chemo/radio-therapy. To date, given the absence of genes within the centromeric regions, no specific molecular events have been identified in this cytogenetic subgroup. We first identified a comprehensive genetic and epigenetic landscape of MDS with dic(1;7)(q10;p10) and compared it to normal controls and other therapy-related Myeloid Neoplasms (t-MNs). RNA-seq showed a unique downregulated signature in dic(1;7) cases, affecting more than 80% of differentially expressed genes. As revealed by pathway and gene ontology analyses, downregulation of ATP-binding cassette (ABC) transporters and of genes related to lipid metabolism, and upregulation of p53 signaling were the most relevant biological features of dicentric-positive MDS. Despite 1q trisomy, more than 50% of 1q deregulated genes were downregulated. This partial gene dosage effect was clarified by epigenetic analysis, which highlighted the presence of a specific hypermethylated pattern on 1q. Furthermore, in a supervised analysis, hypermethylation in all dicentrics clustered at intronic enhancers and was enriched for Krüppel-like transcription factors binding sites. Low expression levels of enhancer putative target genes accounted for more than 30% of the downregulated signature. Our findings demonstrate that alteration of centromeric DNA in dic(1;7) cases imposes a specific transcriptional program, driven by a unique epigenomic signature.
Project description:The unbalanced translocation t(1;7)(q10;p10), generating 1q trisomy and 7q monosomy, is due to centromere-centromere juxtaposition. This dicentric chromosome is a recurrent change in myelodysplastic syndromes (MDS), with half the cases arising after chemo/radio-therapy. To date, given the absence of genes within the centromeric regions, no specific molecular events have been identified in this cytogenetic subgroup. We first identified a comprehensive genetic and epigenetic landscape of MDS with dic(1;7)(q10;p10) and compared it to normal controls and other therapy-related Myeloid Neoplasms (t-MNs). RNA-seq showed a unique downregulated signature in dic(1;7) cases, affecting more than 80% of differentially expressed genes. As revealed by pathway and gene ontology analyses, downregulation of ATP-binding cassette (ABC) transporters and of genes related to lipid metabolism, and upregulation of p53 signaling were the most relevant biological features of dicentric-positive MDS. Despite 1q trisomy, more than 50% of 1q deregulated genes were downregulated. This partial gene dosage effect was clarified by epigenetic analysis, which highlighted the presence of a specific hypermethylated pattern on 1q. Furthermore, in a supervised analysis, hypermethylation in all dicentrics clustered at intronic enhancers and was enriched for Krüppel-like transcription factors binding sites. Low expression levels of enhancer putative target genes accounted for more than 30% of the downregulated signature. Our findings demonstrate that alteration of centromeric DNA in dic(1;7) cases imposes a specific transcriptional program, driven by a unique epigenomic signature.
Project description:The unbalanced translocation t(1;7)(q10;p10), generating 1q trisomy and 7q monosomy, is due to centromere-centromere juxtaposition. This dicentric chromosome is a recurrent change in myelodysplastic syndromes (MDS), with half the cases arising after chemo/radio-therapy. To date, given the absence of genes within the centromeric regions, no specific molecular events have been identified in this cytogenetic subgroup. We first identified a comprehensive genetic and epigenetic landscape of MDS with dic(1;7)(q10;p10) and compared it to normal controls and other therapy-related Myeloid Neoplasms (t-MNs). RNA-seq showed a unique downregulated signature in dic(1;7) cases, affecting more than 80% of differentially expressed genes. As revealed by pathway and gene ontology analyses, downregulation of ATP-binding cassette (ABC) transporters and of genes related to lipid metabolism, and upregulation of p53 signaling were the most relevant biological features of dicentric-positive MDS. Despite 1q trisomy, more than 50% of 1q deregulated genes were downregulated. This partial gene dosage effect was clarified by epigenetic analysis, which highlighted the presence of a specific hypermethylated pattern on 1q. Furthermore, in a supervised analysis, hypermethylation in all dicentrics clustered at intronic enhancers and was enriched for Krüppel-like transcription factors binding sites. Low expression levels of enhancer putative target genes accounted for more than 30% of the downregulated signature. Our findings demonstrate that alteration of centromeric DNA in dic(1;7) cases imposes a specific transcriptional program, driven by a unique epigenomic signature.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
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.