Global gene expression profiling of cells overexpressing SMC3

Giancarlo Ghiselli,Chang-Gong Liu

doi:10.1186/1476-4598-4-34

Giancarlo Ghiselli, Chang-Gong Liu

Open Access

https://doi.org/10.1186/1476-4598-4-34

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Abstract

BackgroundThe Structural Maintenance of Chromosome 3 protein (SMC3) plays an essential role during the sister chromatid separation, is involved in DNA repair and recombination and participates in microtubule-mediated intracellular transport. SMC3 is frequently elevated in human colon carcinoma and overexpression of the protein transforms murine NIH3T3 fibroblasts. In order to gain insight into the mechanism of SMC3-mediated tumorigenesis a gene expression profiling was performed on human 293 cells line stably overexpressing SMC3.ResultsBiotinylated complementary RNA (cRNA) was used for hybridization of a cDNAmicroarray chip harboring 18,861 65-mer oligos derived from the published dEST sequences. After filtering, the hybridization data were normalized and statistically analyzed. Sixty-five genes for which a putative function could be assigned displayed at least two-fold change in their expression level. Eighteen of the affected genes is either a transcriptional factor or is involved in DNA and chromatin related mechanisms whereas most of those involved in signal transduction are members or modulators of the ras-rho/GTPase and cAMP signaling pathways. In particular the expression of RhoB and CRE-BPa, two mediators of cellular transformation, was significantly enhanced. This association was confirmed by analyzing the RhoB and CRE-BPa transcript levels in cells transiently transfected with an SMC3 expression vector. Consistent with the idea that the activation of ras-rho/GTPase and cAMP pathways is relevant in the context of the cellular changes following SMC3 overexpression, gene transactivation through the related serum (SRE) and cAMP (CRE) cis-acting response elements was significantly increased.ConclusionWe have documented a selective effect of the ectopic expression of SMC3 on a set of genes and transcriptional signaling pathways that are relevant for tumorigenesis. The results lead to postulate that RhoB and CRE-BPa two known oncogenic mediators whose expression is significantly increased following SMC3 overexpression play a significant role in mediating SMC3 tumorigenesis.

Highlights

The Structural Maintenance of Chromosome 3 protein (SMC3) is a key component of the nuclear multimeric protein complex named cohesin
Amicroarray analysis of the genome-wide effect of SMC3 overexpression identifies candidate genes mediating SMC3 tumorigenicity The identification of genes that are affected by SMC3 upregulation may provide important clues regarding the biology of this cohesin protein and shed light on the mechanism at the basis of the SMC3-induced tumorigenesis. Toward this end the changes in gene expression caused by sustained SMC3 overexpression were analyzed in fetal kidney 293 cells using a large microarray of human gene-specific oligonucleotides
The results presented provide a molecular signature of the changes that occurs in epithelial cells following SMC3 overexpression

Summary

Introduction

The Structural Maintenance of Chromosome 3 protein (SMC3) is a key component of the nuclear multimeric protein complex named cohesin This complex, which includes SMC1, scc and scc, forms joints between the replicating DNA strands and holds together the sister (page number not for citation purposes). NIH3T3 fibroblasts overexpressing SMC3 lose cell-cell contact inhibition, display anchorage-independent growth and form foci of transformation [5]. These findings support the idea that up-regulation of SMC3 expression is either permissive or sufficient to trigger cell transformation. The Structural Maintenance of Chromosome 3 protein (SMC3) plays an essential role during the sister chromatid separation, is involved in DNA repair and recombination and participates in microtubule-mediated intracellular transport. In order to gain insight into the mechanism of SMC3-mediated tumorigenesis a gene expression profiling was performed on human 293 cells line stably overexpressing SMC3

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