Molecular Cloning and Characterization of the Promoter for the Chinese Hamster DNA Topoisomerase IIα Gene

Ng, Sze Wai; Eder, Joseph P.; Schnipper, Lowell E.; Chan, Victor

doi:10.1074/jbc.270.43.25850

Cited by 22 publications

(16 citation statements)

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“…Using promoter deletion constructs and mutated ICB consensus sites, it has been well documented that the ICBs in the topo II␣ promoter are required for optimal transcriptional activity (Hochhauser et al, 1992;Ng et al, 1995;Park et al, 1995;Herzog and Zwelling, 1997). Isaacs et al (1996) first indicated that the transcription factor complex NF-Y binds to the ICBs of the topo II␣ promoter, and this NF-Yspecific binding has been confirmed by others (Herzog and Zwelling, 1997;Wang et al, 1997), including this present report.…”

Section: Discussionsupporting

confidence: 66%

“…Several laboratories have documented the vital role of multiple ICBs in the topo II␣ promoter for expression of the topo II␣ gene in both human and rodent cell lines (Ng et al, 1995;Herzog and Zwelling, 1997;Wang et al, 1997;Takano et al, 1999). Earlier studies from our lab have demonstrated that successive deletions of each of the five ICBs from the topo II␣ promoter results in progressively reduced promoter activity in mouse embryo fibroblast (10)1 cells and that the activity of the topo II␣ promoter is specifically inhibited by wt p53 but not by mutant p53 (Wang et al, 1997 and Table 1).…”

Section: Binding Of Transcription Factors To the Icbs Of The Topo Ii␣mentioning

confidence: 99%

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Nuclear Factor-Y Binding to the Topoisomerase IIα Promoter Is Inhibited by Both the p53 Tumor Suppressor and Anticancer Drugs

Joshi

Zhong²,

Reed³

et al. 2003

Mol Pharmacol

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Expression of the human DNA topoisomerase II␣ (topo II␣) gene is positively regulated by the binding of the nuclear factor Y (NF-Y) transcription factor to four of five inverted CCAAT boxes (ICBs) located in its promoter. We have demonstrated previously that expression of the p53 tumor suppressor inhibits human topo II␣ promoter activity in murine (10)1 cells. In this report, we demonstrate that the inhibition of topo II␣ gene expression by wild-type p53 correlates with the decreased binding of the transcription factor NF-Y to the first four ICBs of the topo II␣ promoter. The expression of mutant p53 does not affect the binding of NF-Y. In NIH3T3 cells, we show that topo II-targeted drugs inhibit the binding of NF-Y to ICB sites in the topo II␣ promoter. This effect is seen not only with drugs that result in DNA strand breaks but also with drugs that inhibit the catalytic activity of topo II, and even with the mitotic spindle inhibitor, vinblastine. Further experiments with p53-null (10)1 cells treated with these same drugs also demonstrate decreased NF-Y binding to the topo II␣ ICBs. The data presented points to the existence of both p53-dependent and -independent mechanisms for regulating NF-Y binding to ICBs in the topo II␣ promoter and thus the modulation of topo II␣ gene expression.The efficient transcription and replication of DNA requires changes in its double-strand topology at specific times during the cell cycle. These topological alterations are carried out by the ubiquitously expressed, homodimeric nuclear protein, topoisomerase II (topo II). Topo II can relieve supercoiling that results during DNA replication and is an essential enzyme for decatenation of sister chromatids at mitosis. The action of topo II involves the cleavage of one DNA double strand, the passage of a transfer double strand through the break, and religation of the cleaved DNA. During the decatenation cycle, topo II is covalently bound to the cleaved DNA strand, forming an intermediate topo II-DNA cleavable complex. The expression of topo II␣ is lowest in the G 1 phase, increases as the cells traverse S phase, and reaches a maximum at the G 2 /M phase interface (Woessner et al., 1991). This observation is consistent with the association of increased topo II␣ with DNA replication, mitosis, and proliferation.Various transcriptional mechanisms regulate the expression of topo II␣. The promoter region of the topo II␣ gene contains five inverted CCAAT boxes (ICBs), two GC boxes, and an ATF site (Hochhauser et al., 1992). Topo II␣ expression is increased in rapidly proliferating cells after exposure to heat shock (Matsuo et al., 1993) and by the ras oncogene (Chen et al., 1999). On the other hand, topo II␣ expression is down-regulated by wild-type p53 (Wang et al., 1997) or confluence-induced growth arrest . Specific ICBs have been implicated in the regulation of topo II␣ expression by confluence arrest heatshock response (Furukawa et al., 1998), p53 (Wang et al., 1997, and cell cycle dependence (Falck et al., 1999).Topo II␣ is ...

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Section: Discussionsupporting

confidence: 66%

Section: Binding Of Transcription Factors To the Icbs Of The Topo Ii␣mentioning

confidence: 99%

Nuclear Factor-Y Binding to the Topoisomerase IIα Promoter Is Inhibited by Both the p53 Tumor Suppressor and Anticancer Drugs

Joshi

Zhong²,

Reed³

et al. 2003

Mol Pharmacol

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“…However, the topo II␣ promoter differs from other known wt p53-suppressed genes in that it does not contain a TATA box consensus site. The topo II␣ promoter elements that do appear to play a significant role in transcription are the ICEs, of which there are five (37,40,60,63). Studies of the hamster topo II␣ promoter have shown that the ICEs are functionally important for topo II␣ promoter activity and that these sites form complexes with ICE-binding proteins (60).…”

Section: Vol 17 1997 P53 Inhibits Topoisomerase Ii␣ Expression 391mentioning

confidence: 99%

“…The topo II␣ promoter elements that do appear to play a significant role in transcription are the ICEs, of which there are five (37,40,60,63). Studies of the hamster topo II␣ promoter have shown that the ICEs are functionally important for topo II␣ promoter activity and that these sites form complexes with ICE-binding proteins (60). Recent work on the regulation of the human topo II␣ promoter in confluence-arrested cells demonstrated that the second ICE is involved in the down-regulation of topo II␣ expression (40).…”

Section: Vol 17 1997 P53 Inhibits Topoisomerase Ii␣ Expression 391mentioning

confidence: 99%

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Inhibition of DNA Topoisomerase IIα Gene Expression by the p53 Tumor Suppressor

Wang

Zambetti

Suttle

1997

Molecular and Cellular Biology

141

130

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DNA topoisomerase II (topo II) is an essential nuclear enzyme involved in major cellular functions such as DNA replication, transcription, recombination, and mitosis. While an elevated level of topo II␣ is associated with cell proliferation, wild-type (wt) p53 inhibits the expression of various growth-stimulatory genes. To determine if p53 downregulates topo II␣ gene expression, a murine cell line, (10)1val, that expresses a temperature-sensitive p53 was utilized. The (10)1val cells had significantly lower levels of topo II␣ mRNA and protein following incubation for 24 h at 32؇C (p53 with wt conformation) than at 39؇C (p53 with mutant conformation). The effect of p53 on the human topo II␣ gene promoter was determined by using luciferase reporter plasmids containing varying lengths of the topo II␣ promoter transiently cotransfected into p53-deficient (10)1 cells together with wt or mutant p53 expression plasmids. Transcription from the full-length (bp ؊557 to ؉90) topo II␣ promoter was decreased 15-fold by wt p53 in a concentration-dependent manner, whereas mutant p53 exerted much weaker inhibition. Consecutive deletion of the five inverted CCAAT elements (ICEs) from the topo II␣ promoter reduced both the basal promoter activity and wt p53-induced suppression. Transcription of the minimal promoter (؊32 to ؉90), which contains no ICE, was slightly stimulated by wt or mutant p53 expression. When point mutations were introduced into the most proximal ICE (؊68), the inhibitory effect of wt p53 was alleviated and stimulation of topo II␣ expression resulted. Our study suggests that wt p53 functions as a transcriptional repressor of topo II␣ gene expression, possibly through a functional interaction with specific ICEs. Inactivation of wt p53 may reduce normal regulatory suppression of topo II␣ and contribute to abortive cell cycle checkpoints, accelerated cell proliferation, and alterations in genomic stability associated with neoplasia.DNA topoisomerase II (topo II) is a ubiquitous enzyme that can alter the topological state of DNA and untangle intertwined DNA helices (for reviews, see references 79 and 80). As such, topo II plays an essential role in several cellular events, such as replication (20), chromatin condensation (76), and sister chromatid segregation (20,76). Functioning as a homodimer, topo II binds double-stranded DNA and attaches covalently to both strands of the helix, resulting in DNA breaks in each strand. Upon binding of ATP to the topo II-DNA complex, a second DNA helix can pass through the cleavable complex, and this is followed by hydrolysis of ATP and resealing of the cleaved double-stranded DNA (7, 10). The ability of topo II to pass duplex DNA molecules allows the enzyme to separate fully replicated DNA molecules prior to chromosome segregation (61). There are two topo II isoforms, topo II␣ (170 kDa) and topo II␤ (180 kDa), present in mammalian cells. Although both enzymes are closely related in structure (72% identical amino acid residues [42]), they differ in important biochemical and pharmac...

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Topoisomerase IIα gene expression is regulated by the p53 tumor suppressor gene in nonsmall cell lung carcinoma patients

Liu

Huang

Kameyama

et al. 2002

Cancer

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BACKGROUND Topoisomerase IIα (Topo IIα) is an essential nuclear enzyme for chromosome segregation during mitosis. Previous experimental studies using cell lines reported that Topo IIα expression was negatively regulated by wild‐type p53 through the gene's promoter region. METHODS Surgically resected tumor specimens from 98 nonsmall cell lung carcinoma (NSCLC) patients who were not treated with preoperative chemotherapy were studied. Quantitative reverse‐transcription polymerase chain reaction analysis was done to evaluate Topo IIα gene expression. Polymerase chain reaction single strand conformation polymorphism following sequencing was performed to investigate mutations of p53. RESULTS Topo IIα gene expression in squamous cell carcinomas was significantly higher than in adenocarcinomas (P = 0.0007). Topo IIα gene expression in moderately differentiated tumors and poorly differentiated tumors was significantly higher than in well differentiated tumors (P = 0.0032 and P = 0.0005, respectively). Thirty nine tumors (40%) had mutations of p53. Topo IIα gene expression in tumors with mutant p53 was significantly higher than in those with wild‐type p53 (P = 0.0224). CONCLUSIONS The current study suggests that Topo IIα gene expression is regulated by p53 gene status in NSCLC patients and that the overexpression of Topo IIα induced by mutant p53 might cause more aggressive carcinogenesis. Cancer 2002;94:2239–47. © 2002 American Cancer Society. DOI 10.1002/cncr.10450

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Molecular Cloning and Characterization of the Promoter for the Chinese Hamster DNA Topoisomerase IIα Gene

Cited by 22 publications

References 32 publications

Nuclear Factor-Y Binding to the Topoisomerase IIα Promoter Is Inhibited by Both the p53 Tumor Suppressor and Anticancer Drugs

Nuclear Factor-Y Binding to the Topoisomerase IIα Promoter Is Inhibited by Both the p53 Tumor Suppressor and Anticancer Drugs

Inhibition of DNA Topoisomerase IIα Gene Expression by the p53 Tumor Suppressor

Topoisomerase IIα gene expression is regulated by the p53 tumor suppressor gene in nonsmall cell lung carcinoma patients

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