Dataset Information

Relationships linking amplification level to gene over-expression in gliomas.

ABSTRACT:

Background

Gene amplification is thought to promote over-expression of genes favouring tumour development. Because amplified regions are usually megabase-long, amplification often concerns numerous syntenic or non-syntenic genes, among which only a subset is over-expressed. The rationale for these differences remains poorly understood.

Methodology/principal finding

To address this question, we used quantitative RT-PCR to determine the expression level of a series of co-amplified genes in five xenografted and one fresh human gliomas. These gliomas were chosen because we have previously characterised in detail the genetic content of their amplicons. In all the cases, the amplified sequences lie on extra-chromosomal DNA molecules, as commonly observed in gliomas. We show here that genes transcribed in non-amplified gliomas are over-expressed when amplified, roughly in proportion to their copy number, while non-expressed genes remain inactive. When specific antibodies were available, we also compared protein expression in amplified and non-amplified tumours. We found that protein accumulation barely correlates with the level of mRNA expression in some of these tumours.

Conclusions/significance

Here we show that the tissue-specific pattern of gene expression is maintained upon amplification in gliomas. Our study relies on a single type of tumour and a limited number of cases. However, it strongly suggests that, even when amplified, genes that are normally silent in a given cell type play no role in tumour progression. The loose relationships between mRNA level and protein accumulation and/or activity indicate that translational or post-translational events play a key role in fine-tuning the final outcome of amplification in gliomas.

SUBMITTER: Vogt N

PROVIDER: S-EPMC2999539 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Relationships linking amplification level to gene over-expression in gliomas.

Vogt Nicolas N Gibaud Anne A Almeida Anna A Ourliac-Garnier Isabelle I Debatisse Michelle M Malfoy Bernard B

PloS one 20101208 12

<h4>Background</h4>Gene amplification is thought to promote over-expression of genes favouring tumour development. Because amplified regions are usually megabase-long, amplification often concerns numerous syntenic or non-syntenic genes, among which only a subset is over-expressed. The rationale for these differences remains poorly understood.<h4>Methodology/principal finding</h4>To address this question, we used quantitative RT-PCR to determine the expression level of a series of co-amplified g ...[more]

PMID: 21170331

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Dataset Information

Relationships linking amplification level to gene over-expression in gliomas.

Background

Methodology/principal finding

Conclusions/significance

Publications

Relationships linking amplification level to gene over-expression in gliomas.

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