Project description:By comparing the expression levels of genes between carriers of Nijmegen Breakage Syndrome and non-carriers, we showed that NBS carriers have a distinct gene expression phenotype. Keywords: Cell Line Comparison
Project description:By comparing the expression levels of genes between carriers of Nijmegen Breakage Syndrome and non-carriers, we showed that NBS carriers have a distinct gene expression phenotype. Experiment Overall Design: Gene expression analysis using Affymetrix Human Focus arrays; comparison of expression levels of genes using t-statistic and identification of genes that allow classification of individuals as carriers or non-carriers by linear discriminant analysis.
Project description:Nijmegen breakage syndrome (NBS) is a rare genetic disorder inherited in an autosomal recessive pattern associated with an increased risk of developing lymphoproliferative disorders, mainly non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL). This work presents a patient previously diagnosed with Nijmegen breakage syndrome who rapidly developed T-NHL despite of constant medical supervision. Cytogenetic karyotype and microarray tests revealed complex aberrations, indicating enhanced chromosomal instability.
Project description:Nijmegen-breakage syndrome (NBS, OMIM #251260) is an autosomal recessive chromosomal instability syndrome characterized by a very distinct phenotype (microcephaly, growth retardation, immunodeficiency) associated with increased predisposition to develop malignancies, particularly of lymphoid origin (by the age of 20 years, over 40% of NBS patients develop cancer). Immunological lineage of lymphomas in NBS significantly differs from Non-Hodgkin Lymphomas (NHL) entities observed in general pediatric population as well as in primary immunodeficiencies. There is a strong predominance of diffuse large B-cell lymphoma (DLBCL) and T cell lymphoblastic lymphoma (T-LBL/ALL), all showing clonal Ig/TCR rearrangements. In the current study we aimed to examined gene expression signature of metabolic pathways in DLBCL cells.
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.
Project description:NBS1 (Nbn in Mus musculus) is a critical component of the MRN (MRE11/RAD50/NBS1) complex, which regulates ATM- and ATR-mediated DNA damage response (DDR) pathways. NBS1 mutations cause the human genomic instability syndrome Nijmegen Breakage Syndrome (NBS), in which microcephaly and intellectual disability are marked neuronal deficits. NBS1 is essential for life, because of its function in the DDR to ensure proliferation and preventing the cell death of replicating cells. However, the function of NBS1 in postmitotic cells is unclear. To explore the possible role of Nbs1 in non-dividing cells and the effection of its deletion on gene expression, RNA-seq was carried out with Nbs1 induced knockout liver samples, in which most cells are postmitotic.
Project description:Mutations of NBS1 gene result in Nijmegen breakage syndrome (NBS), and the gene encodes NBS1 that forms a complex with MRE11 and RAD50 and participates in DNA damage repair. However, the molecular mechanism by which the mutations of NBS1 cause clinical phenotypes of NBS, such as craniofacial dysmorphism, is still unclear. Here, we show that NBS1 localizes at the rDNA loci in the nucleoli and interacts with ribosome RNA (rRNA) transcription machinery including RNA polymerase I (Pol I) and TCOF1. Loss of NBS1 impairs Pol I-dependent transcription of pre-rRNA and induces nucleolar stress. In particular, lacking Nbs1 in mouse neural crest cells not only leads to the reduction of ribosome biogenesis but also craniofacial abnormalities during prenatal development. Moreover, the C-terminus of NBS1 is associated with pre-rRNA and a number of pre-rRNA processing factors, which may also facilitate pre-rRNA maturation. Taken together, our study reveals the functions of NBS1 in rRNA biogenesis.