title: Alternative splicing of neurofibromatosis type 1 gene transcript in malignant brain tumors: PCR analysis of frozen-section mRNA.
abstract: The neurofibromatosis type 1 (NF1) gene encodes a 360-residue region showing significant homology to the catalytic domains of both mammalian GTPase-activating protein (GAP) and yeast IRA protein. The product of the GAP-related domain of the NF1 gene (NF1-GRD) has been shown to stimulate ras GTPase and consequently to inactivate ras protein. We previously reported that the NF1-GRD has two types of transcripts, type I and type II, which are generated by an alternative splicing mechanism, and that the differential splicing of the NF1-GRD may be related to differentiation of neuroectodermal cells. Here we examined the differential expression of type I and type II transcripts of NF1-GRD in clinical samples of supratentorial malignant brain tumors by the RNA-polymerase chain reaction (PCR) method using frozen tissue sections. Our observations revealed that normal cerebrum predominantly expressed the type II NF1-GRD transcript, whereas primitive neuroectodermal tumors predominantly expressed the type I transcript. Additionally, although the type I/type II ratio in astrocytomas varied widely among tissue samples, all glioblastomas showed higher type I/type II ratios than adjacent brain samples. The RNA-PCR analysis using frozen tissue sections is a useful and sensitive method for detecting genetic markers in clinical tissue samples.
authors.affiliation: Department of Neuro-Oncology, University of Texas M. D. Anderson Cancer Center, Houston 77030.
authors.forename: H
authors.initials: H
authors.lastname: Mochizuki
authors.forename: T
authors.initials: T
authors.lastname: Nishi
authors.forename: J M
authors.initials: JM
authors.lastname: Bruner
authors.forename: P S
authors.initials: PS
authors.lastname: Lee
authors.forename: V A
authors.initials: VA
authors.lastname: Levin
authors.forename: H
authors.initials: H
authors.lastname: Saya
mesh_terms: D001254:Astrocytoma / Q000378:metabolism* / Q000473:pathology; D001483:Base Sequence; D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D015870:Gene Expression; D016514:Genes, Neurofibromatosis 1 / Q000502:physiology*; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012326:RNA Splicing; D012333:RNA, Messenger / Q000032:analysis*; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger