Mutational and expression analysis of the reelin pathway components CDK5 and doublecortin in gangliogliomas.
Gangliogliomas represent highly differentiated glioneuronal tumors frequently occurring in young patients with focal epilepsies. Dysplastic neurons are a neuropathological hallmark of this neoplasm. Here, we have analyzed two major components of the reelin pathway associated with neuronal migration and cortical cytoarchitecture in gangliogliomas, i.e., cyclin-dependent kinase 5 (CDK5) and doublecortin (DCX). The genomic structure of human CDK5 was identified by an " in silico" cloning approach using the "high throughput genomic sequencing" (htgs) databank, NCBI BLAST 2.1. DNA sequence analysis of CDK5 and DCX was carried out in tissue samples obtained from 23 patients and compared with control DNA from non-affected individuals ( n=100). For gene expression analysis of CDK5 and DCX, a quantitative real time reverse transcription-PCR TaqMan assay was used with mRNA from gangliogliomas ( n=22) and non-lesional central nervous tissue control tissue ( n=7). The human CDK5 gene is located on chromosome 7q36 and contains 12 exons. Its coding sequence reveals 90.1% homology to the mouse counterpart. A novel pseudogene of CDK5 was found on chromosome 8. While the mutational analysis of CDK5 and DCX did not reveal any sequence alterations in gangliogliomas, a lower expression was observed for both genes in tumor compared to control tissue samples. The present data indicate that mutations of CDK5 and DCX genes are not involved in the development of gangliogliomas. A novel pseudogene on chromosome 8 has to be taken into account for future studies on CDK5.
Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany. albert_becker@uni-bonn.de
Albert J
AJ
Becker
Holger
H
Klein
Thomas
T
Baden
Ludwig
L
Aigner
Sabine
S
Normann
Christian E
CE
Elger
Johannes
J
Schramm
Otmar D
OD
Wiestler
Ingmar
I
Blümcke
D000818:Animals; D001483:Base Sequence; D001932:Brain Neoplasms / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000235:genetics*; D004252:DNA Mutational Analysis; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000235:genetics*; D030561:Databases, Nucleic Acid; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D004827:Epilepsy / Q000209:etiology; D018303:Ganglioglioma / Q000150:complications / Q000235:genetics*; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011544:Pseudogenes / Q000235:genetics*; D000091042:Reelin Protein
C000714328:DCX protein, human; D017931:DNA Primers; D004273:DNA, Neoplasm; C000714847:Dcx protein, mouse; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D000091042:Reelin Protein; D051360:Cyclin-Dependent Kinase 5; C495905:CDK5 protein, human; C495906:Cdk5 protein, mouse; D018844:Cyclin-Dependent Kinases; C000717127:RELN protein, human; C000717128:Reln protein, mouse