HL-60 세포에서 12-O-tetradecanoyl-phorbol-13-acetate에 의한 DNA topoisomerse Ⅱα 유전자 전사조절에 관련된 trans-acting factors의 특성에 관한 연구 = Characterization of novel trans-acting factor bound on the DNA topoisomerase Ⅱα promoter during TPA-dependent differentiation of HL-60 cells

다국어 초록 (Multilingual Abstract)

DNA topoisomerase IIa plays an important role in events leading to mitosis and Topo IIa gene is regulated at cell-cycle dependent manner. To gain insight on the mechanism of transcriptional repression of Topo IIa gene, the binding pattern of nuclear proteins to various cis-elements in the Topo IIa gene upstream region has been investigated with DNase I footprinting and DNA mobility shift assay. HL-60 cells were arrested at G_/G_ phase after TPA treatment in FACS analysis. The level of Topo IIa mRNA and unknotting activity were reduced at 24 hours after exposure with TPA. The unclear factors, were which newly induced during reduction of Topo IIa mRNA after TPA treatment, bound with at least four sites : I-CCAAT-1 at -68 bp, I-CCAAT-2 at -108 bp, I-CCAAT-4 at -259 bp and novel cis-element at -196 (Topo IIa specific sequence, TSS : upper strand, 5-TAGTCCCGCCTCCCTAACCT-3). The DNase I protection pattern showed the same result with the control after addition of competitors including TSS and I-CCAAT. DNA mobility shift assays using oligonucleotides containing the I-CCAATs showed one specific DNA-protein complex and the competition studies indicated apparent binding of ICB-1~4 to the same protein while ICB-5 bound to a different protein. DNA mobility shift assays using oligonucleotide containing the TSS showed two specific DNA-protein complexes and the TSSBP bound to TSS-specific and novel trans-acting factor. TPA-dependet induction of TSS binding protein (TSSBP) reduced after pretreatment of staurosporin and completely vanished after pretreatment of cycloheximide. These results suggest that the transcriptional repression of Topo IIa gene during TPA-induced differentiation of HL-60 cells may be mediated by four transacting factors that are newly induced by TPA and TSSBP is a novel trans-acting factor.

목차 (Table of Contents)

• 목차
• I. 서론 = 1
• II. 실험재료 및 방법 = 3
• III. 결과 = 11
• IV. 고찰 = 33
• V. 결론 = 37
• 참고문헌 = 38
• Abstract = 46