Project description:We conducted microarray-based comparative genomic hybridization (array-CGH) with a DNA chip carrying 2,464 BAC clones to examine genomic aberrations of 236 neuroblastomas (112 sporadic and 124 mass screening-detected). In paralell, gene-expression profiling was also performed by using in-house cDNA microarrays. Keywords: Comparative genomic hybridization
Project description:We conducted microarray-based comparative genomic hybridization (array-CGH) with a DNA chip carrying 2,464 BAC clones to examine genomic aberrations of 236 neuroblastomas (112 sporadic and 124 mass screening-detected). In paralell, gene-expression profiling was also performed by using in-house cDNA microarrays. Keywords: Comparative genomic hybridization A UCSF BAC array carrying 2,464 clones, which covers the whole human genome at roughly 1.2-Mb resolution, was used. The 500-ng aliquots of tumors and reference DNAs were labeled by random priming with each Cy3-dCTP and Cy5-dCTP (Amersham Pharmacia, Piscataway, NJ). Hybridization was performed as previously reported [Pinkel D, et al. Nat Genet 1998;20:207-11.]. UCSF Spot and UCSF Sproc programs to analyze values for spotted clones [Jain AN, et al. Genome Res 2002;12:325-32.] were used.
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:This study constructed a non-gapped bacterial artificial chromosomes (BAC) array containing 3604 BAC clones covering 18 lung cancer-related chromosome imbalance hotspot regions. Using this specialized array, DNA from tumor and normal tissues of 40 Asian and 20 Caucasian non-small cell lung cancer (NSLCL) patients was analyzed by array-comparative genomic hybridization (array-CGH). Block-wise normalization and a Bayes regression approach were used to refine the chromosomal imbalance regions identified by array-CGH. The array-CGH results then analyzed by MetaCore software to identify potential cancer-related genes. Finally, 273 genes showing significantly associated with molecular pathway, cancer biomarker, and gene ontology database, such as ZNF322A on 6p22.1, ARHGAP19 on 10q24.1, FRAT2 on 10q24.1, and PAFAH1B1 on 17p13.3 functioning in MAPK, Rho GTPase, and Wnt, and motility control pathways with frequent copy number gain were selected. This study mapped concisely the novel oncogenes or tumor suppressor genes in lung cancer and revealed insights of difference on chromosomal imbalance between lung cancer from Asian and Caucasian.