Mechanism of Functional Switching of C-MYC: Formation of Different Protein Complexes and Expression of Activities in DNA Replication, Transcription and Apoptosis Induction during the Cell Cycle.

C-MYC功能转换机制：细胞周期中不同蛋白复合物的形成以及DNA复制、转录和凋亡诱导活性的表达。

基本信息

批准号：
10044226
负责人：
ARIGA Sanae
金额：
$ 2.56万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

C-MYC has been suggested to be involved in cell proliferation, differentiation, transformation and apoptosis. We supposed that C-MYC plays such kaleidoscopic functions in partnership with various proteins. Besides the reported Max family proteins forming dimers with C-MYC via the basic helix-loop-helix leucine-zipper structure (bHLHZip) in the C-terminal region of C-MYC, we have screened proteins which interacts with C-MYC via the myc boxes, well-conserved among the myc family, in the N-terminal region. We applied the yeast two-hybrid system in the screening and have obtained several novel partner proteins including AMY-1 and MM-1 as well as reported proteins, CBF/NF-Y, ORC1, CDC6 and cdk inhibitor p21. MSSP, which we have also identified as a C-MYC binding protein, recognized the myc boxes. These proteins were examined for their functions both in vitro and in vivo and were classified to the categories including factors for transcription (AMY-1, MM-1 and CBF/NF-Y), DNA replication (MSS … More P, ORC1 and CDC6) and cell-cycle movement (p21). As for the transcriptional activity of C-MYC, only AMY-1 acted as a positive regulatory factor while the others, MM-1 and CBF/NF-Y, were negative factors. AMY-1 induced the erythrocyte differentiation of K562 cells. Male transgenic mice of the AMY-1 gene were sterile and the RII domain of AKAP-84, the binding site of the regulatory subunit of A-kinase which is important in spermatogenesis, was cloned as a AMY-1 binding protein. AMY-1 was thus suggested to inhibit the appropriate localization of the A-kinase and to induce apoptosis of spermatogenic cells. In addition, AMY-1 was found to bind to WAVE/AKAP-149, a factor involved in actin polimerization. MM-1 has a character for putatice tumor suppressor. The substitution of the amino acid #157 of MM-1 from alanine to arginine was frequently observed in the cells and tissues of lymphoma, leukemia and tongue cancer. The arginine mutation abrogated the negative effects of MM-1 on C-MYC. ORC1, a remodeling factor of chromatin, bound to C-MYC competitively with SNF5, an MSSP family protein, to release C-MYC from chromatin. Null-mutation of MSSP tended to be lethal during developmental stage. These findings altogether suggest that C-MYC binding proteins play roles at crucial steps of cell maturation, fertilazation in addition to the modulation of versatile functions of C-MYC. Less

c-myc已被认为参与细胞增殖，分化，转化和凋亡。我们期望C-MYC与各种蛋白质合作发挥这种万花筒功能。除了据报道，在C-MYC的C末端区域中，通过基本的Helix-Loop-helix亮氨酸Zipper结构（BHLHZIP）形成C-MYC的最大家族蛋白除了C-MYC形成二聚体外，我们还筛选了筛选的蛋白质，这些蛋白质通过MYC盒与C-MYC相互作用，在MYC家族中与C-MYC相互作用，在N-term末端区域中良好的MYC家族。我们在筛选中应用了酵母双杂交系统，并获得了几种新型伴侣蛋白，包括AMY-1和MM-1，以及报道的蛋白质CBF/NF-Y，ORC1，CDC6，CDC6和CDK抑制剂P21。我们也确定为C-MYC结合蛋白的MSSP识别MYC盒。检查了这些蛋白质的体外和体内功能，并被分类为类别，包括转录因素（AMY-1，MM-1和CBF/NF-Y），DNA复制（MSS…更多P，ORC1和CDC6）和细胞周期运动（P21）。至于C-MYC的转录活性，仅AMY-1充当了积极的调节因素，而其他AMY-1则是MM-1和CBF/NF-Y，是负因素。 AMY-1诱导K562细胞的红细胞分化。 AMY-1基因的雄性转基因小鼠是无菌的，AKAP-84的RII结构域，AKAP-84的RII结构域是A-激酶的调节亚基的结合位点，在精子发生中很重要，被克隆为AMY-1结合蛋白。因此，建议AMY-1抑制A-激酶的适当定位并诱导精子细胞的凋亡。此外，发现AMY-1与WAVE/AKAP-149结合，这是肌动蛋白聚凝结涉及的一个因素。 MM-1具有用于抑制性肿瘤的特征。在淋巴瘤，白血病和舌癌的细胞和组织中，经常观察到MM-1的氨基酸＃157从丙氨酸取代。精氨酸突变促使MM-1对C-MYC的负面影响。 ORC1是染色质的重塑因子，与MSSP家族蛋白SNF5竞争与C-MYC结合，以从染色质释放C-MYC。在发育阶段，MSSP的无效倾向于致命。这些发现完全表明C-MYC结合蛋白在细胞成熟的关键步骤中起着作用，除了调节C-MYC多功能功能外，受精。较少的