title: Identification and characterization of human beta 2-chimaerin: association with malignant transformation in astrocytoma.
abstract: Molecular processes resulting in the malignant transformation from low- to high-grade astrocytoma remain poorly understood. Using reverse transcriptase PCR, we identified a gene that is differentially expressed in normal brain and low-grade astrocytoma compared to glioblastoma tissues. This gene is identical to human beta 2-chimaerin, which encodes a 468-amino acid GTPase-activating protein for p21rac. The gene was localized to human chromosome 7p15.3 by fluorescence in situ hybridization mapping. Human beta 2-chimaerin is expressed in a variety of human tissues, with the highest expression level detected in human brain and pancreas. RNase protection assays indicated that the expression level of this gene is high in all the normal brain and low-grade astrocytoma samples tested compared to malignant gliomas. The down-regulation of beta 2-chimaerin expression in the high-grade gliomas suggests that decreased expression of this gene may be a feature of progression in the development of malignant glioma.
authors.affiliation: Brain Tumor Center of the Department of Neurological Surgery, Cleveland Clinic Foundation, Ohio 44195, USA.
authors.forename: S
authors.initials: S
authors.lastname: Yuan
authors.forename: D W
authors.initials: DW
authors.lastname: Miller
authors.forename: G H
authors.initials: GH
authors.lastname: Barnett
authors.forename: J F
authors.initials: JF
authors.lastname: Hahn
authors.forename: B R
authors.initials: BR
authors.lastname: Williams
mesh_terms: D000595:Amino Acid Sequence; D001254:Astrocytoma / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000737:chemistry / Q000235:genetics*; D002874:Chromosome Mapping; D002897:Chromosomes, Human, Pair 7; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics*; D009857:Oncogenes; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D009363:Neoplasm Proteins; C079844:beta-chimaerin