Project description:10 patients with Intellectual Disability diagnosed with a clinically relevant copy number change, selected to assess the dection performance of alternative platforms. 10 Affymetrix arrays were performed according to the manufacturer's directions on DNA extracted from peripheral blood samples.
Project description:10 patients with Intellectual Disability diagnosed with a clinically relevant copy number change, selected to assess the dection performance of alternative platforms.
Project description:Intellectual disability (ID) is a clinically important disease and a most prevalent neurodevelopmental disorder. The etiology and pathogenesis of ID are poorly recognized. Exome sequencing revealed a homozygous missense mutation in the POLR3B gene in a consanguineous family with three Intellectual disability with craniofacal anomalies patients. POLR3B gene encoding the second largest subunit of RNA polymerase III. To explore how genetic variants alter cell expression in ID patients, RNA sequencing on blood samples was performed and to obtain insights into the biological pathways influenced by POLR3B mutation, we applied our RNA-Seq data to several gene ontology programs such as ToppGene, Enrichr, KEGG. We detected a significant decrease expression of several spliceosomal RNAs, ribosomal proteins and transcription factors in our ID patients. We hypothesize that POLR3B mutation dysregulates the expression of some important transcription factors, ribosomal and spliceosomal genes and impairments in protein synthesis and splicing mediated in part by transcription factors such as FOXC2, GATA1, .. contribute to impaired neuronal function and concurrence of intellectual disability and craniofacial anomalies in our patients. Our study highlights the emerging role of spliceosome and ribosomal proteins in intellectual disability.
Project description:Mate pair sequencing for the detection of balanced and unbalanced chromosomal aberrations in patients with intellectual disability and congenital malformations
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.