Cell-cycle regulation of the DNA topoisomerase IIalpha promoter is mediated by proximal CCAAT boxes: possible involvement of acetylation.
Expression of DNA topoisomerase (topo) IIalpha is cell-cycle-regulated, with its peak in G(2)/M and its lowest level in G(0)/G(1). In agreement with this expression pattern, we have shown that the topo IIalpha gene promoter shows cell-cycle-dependent activity, which is repressed in G(0)/G(1) and activated exclusively in G(2)/M. However, the promoter sequence reveals no canonical CDE/CHR motifs, repressor elements commonly found in promoters of late S/G(2)-activated genes. Here, we show that at least two of the three proximal inverted CCAAT boxes (ICBs) are responsible for the G(2)/M-specific activation of the topo IIalpha promoter. Using antibody supershift experiments, we identify NF-Y as the ICB-binding transcription factor. However, the expression profile and binding capacity of NF-Y were constant during the cell cycle, suggesting a more global mechanism in topo IIalpha promoter regulation. Interestingly, we find that trichostatin A (TSA), a specific histone deacetylase inhibitor, greatly enhances topo IIalpha promoter activity in an ICB-dependent manner. In addition, the effect of TSA is predominant in G(0)/G(1) and less obvious in G(2)/M. Our data, along with the recent findings that NF-Y associates in vivo with histone acetyltransferases (HATs), strongly suggest a mechanism, in which histone deacetylation plays a crucial role in the G(0)/G(1)-specific repression of the topo IIalpha promoter, and NF-Y recruits HATs to the promoter region, thereby stimulating histone acetylation and activating transcription in G(2)/M.
Adachi
N
N
Kihara Institute for Biological Research, Yokohama City University, Maioka-cho 641-12, Totsuka-ku, Yokohama, Japan.
Nomoto
M
M
Kohno
K
K
Koyama
H
H
D016475:3T3 Cells; D000107:Acetylation; D000818:Animals; D000951:Antigens, Neoplasm; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins; D002453:Cell Cycle / Q000502:physiology*; D004250:DNA Topoisomerases, Type II / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D016195:G2 Phase / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008938:Mitosis / Q000502:physiology; D009154:Mutation; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism
D000951:Antigens, Neoplasm; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D007527:Isoenzymes; D009841:Oligonucleotides; D011993:Recombinant Fusion Proteins; C012589:trichostatin A; D008156:Luciferases; D004250:DNA Topoisomerases, Type II