Genomic structure and chromosomal mapping of the gene coding for ICBP90, a protein involved in the regulation of the topoisomerase IIα gene expression

Hopfner, Raphaël; Mousli, Marc; Garnier, Jean‐Marie; Redon, Richard; Manoir, Stanislas du; Chatton, Bruno; Ghyselinck, Norbert B.; Oudet, P; Bronner, Christian

doi:10.1016/s0378-1119(01)00371-7

Cited by 38 publications

(37 citation statements)

References 17 publications

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“…In the discussion of the article, it is described that they could not recognize the sequence of exon F (2.6 kb) of the ICBP90 gene in the Homo sapiens chromosome 19 genomic contig, NT011255 (GenBank), at 19p13.3, but found this exon in a BAC (8). Exon F reported by Hopfner et al (9) was composed of 11 exons. AF220266 and AF220267 were the ICBP90 5ЈUTR and 3ЈUTR sequence determined by Hopfner et al (9).…”

Section: Resultsmentioning

confidence: 94%

See 1 more Smart Citation

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹

Muto¹,

Fujimori²,

Nenoi³

et al. 2006

Radiation Research

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Section: Resultsmentioning

confidence: 94%

“…Exon F reported by Hopfner et al (9) was composed of 11 exons. AF220266 and AF220267 were the ICBP90 5ЈUTR and 3ЈUTR sequence determined by Hopfner et al (9). Panel B: Exon 3 is composed of exons 3a and 3b.…”

Section: Resultsmentioning

confidence: 97%

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹

Muto¹,

Fujimori²,

Nenoi³

et al. 2006

Radiation Research

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“…Rb activity in cell cycle machinery can also be regulated at the transcriptional and protein levels by the transcription factor ICBP90 (Hopnefer, 2000). ICBP90 (inverted CCAAT box binding protein of 90 kDa) is a transcriptional regulator of the topoisomerase II alpha gene and it has also two consensus binding sites for pRb in its primary sequence.…”

Section: Rb and Cell Cyclementioning

confidence: 99%

RB and cell cycle progression

2006

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The Rb protein is a tumor suppressor, which plays a pivotal role in the negative control of the cell cycle and in tumor progression. It has been shown that Rb protein (pRb) is responsible for a major G1 checkpoint, blocking S-phase entry and cell growth. The retinoblastoma family includes three members, Rb/p105, p107 and Rb2/p130, collectively referred to as 'pocket proteins'. The pRb protein represses gene transcription, required for transition from G1 to S phase, by directly binding to the transactivation domain of E2F and by binding to the promoter of these genes as a complex with E2F. pRb represses transcription also by remodeling chromatin structure through interaction with proteins such as hBRM, BRG1, HDAC1 and SUV39H1, which are involved in nucleosome remodeling, histone acetylation/ deacetylation and methylation, respectively. Loss of pRb functions may induce cell cycle deregulation and so lead to a malignant phenotype. Gene inactivation of pRB through chromosomal mutations is one of the principal reasons for retinoblastoma tumor development. Functional inactivation of pRb by viral oncoprotein binding is also shown in many neoplasias such as cervical cancer, mesothelioma and AIDS-related Burkitt's lymphoma.

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“…Since these cells are pRB and p53 null cells, it is likely that the basal expression of E2F-1 is sufficient to induce submaximal ICBP90 and TopoIIa expression, which would consequently minimize the effect of an E2F-1 overexpression on the cell sensitivity to anti-TopoII drugs (Yang et al, 2001). Furthermore, we believe that the deregulation of the ICBP90 expression in cancer cells involves E2F considering that high E2F activity has been documented in colon tumours and gastric carcinomas (Lemass et al, 1998;Suzuki et al, 1999), that an E2F binding site exits in the promoter of the ICBP90 gene (Hopfner et al, 2001) and that overexpression of E2F-1 has little effect on ICBP90 expression in cancer cell lines vs noncancer cell lines (present results).…”

mentioning

confidence: 90%

“…We have also recently shown that transient overexpression of ICBP90 could overcome cell contact inhibition by forcing TopoIIa expression in primary cultures of human lung fibroblasts . Interestingly, the promoter of the ICBP90 gene contains an E2F-consensus binding site close to one of the transcription start sites (Hopfner et al, 2001). The E2F-1 is a member of the E2F family that is found to be elevated in cancer cells (Lemass et al, 1998;Suzuki et al, 1999).…”

mentioning

confidence: 99%

ICBP90 belongs to a new family of proteins with an expression that is deregulated in cancer cells

et al. 2003

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ICBP90 (Inverted CCAAT box Binding Protein of 90 kDa) is a recently identified nuclear protein that binds to one of the inverted CCAAT boxes of the topoisomerase IIa (TopoIIa) gene promoter. Here, we show that ICBP90 shares structural homology with several other proteins, including Np95, the human and mouse NIRF, suggesting the emergence of a new family of nuclear proteins. Towards elucidating the functions of this family, we analysed the expression of ICBP90 in various cancer or noncancer cell lines and in normal or breast carcinoma tissues. We found that cancer cell lines express higher levels of ICBP90 and TopoIIa than noncancer cell lines. By using cell-cycle phase-blocking drugs, we show that in primary cultured human lung fibroblasts, ICBP90 expression peaks at late G1 and during G2/M phases. In contrast, cancer cell lines such as HeLa, Jurkat and A549 show constant ICBP90 expression throughout the entire cell cycle. The effect of overexpression of E2F-1 is more efficient on ICBP90 and TopoIIa expression in noncancer cells (IMR90, WI38) than in cancer cells (U2OS, SaOs). Together, these results show that ICBP90 expression is altered in cancer cell lines and is upregulated by E2F-1 overexpression with an efficiency depending on the cancer status of the cell line.

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Genomic structure and chromosomal mapping of the gene coding for ICBP90, a protein involved in the regulation of the topoisomerase IIα gene expression

Cited by 38 publications

References 17 publications

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹

RB and cell cycle progression

ICBP90 belongs to a new family of proteins with an expression that is deregulated in cancer cells

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Genomic structure and chromosomal mapping of the gene coding for ICBP90, a protein involved in the regulation of the topoisomerase IIα gene expression

Cited by 38 publications

References 17 publications

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP951

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP951

RB and cell cycle progression

ICBP90 belongs to a new family of proteins with an expression that is deregulated in cancer cells

Contact Info

Product

Resources

About

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹

Isolation and Characterization of a Novel Human Radiosusceptibility Gene,NP95¹