Functional analysis epigenetics regulators in carcinogenesis

人们一直致力于了解基因突变导致恶性转化的机制。如今，还需要对癌症中的表观遗传突变进行研究。在这个项目中，我们专注于表观遗传学调节剂（组蛋白修饰酶和组蛋白变体），在化学诱导的肝癌发生过程中上调。组蛋白修饰酶过度表达对肝癌发生的影响我们通过RT-PCR、DNA微阵列和Western印迹分析鉴定了肝癌发生过程中诱导的组蛋白修饰酶。其中组蛋白乙酰转移酶调节突变ras癌基因介导的转化活性。组蛋白去乙酰化酶是另一种促进软琼脂糖贴壁生长的调节因子.组蛋白修饰酶的过度表达对肿瘤标志物基因表达的影响：胎盘型谷胱甘肽转移酶（GST-P）在肿瘤发生过程中被特异性地显著诱导。 ...更多信息 肝癌发生，被认为是可靠的肿瘤标志物。转录因子Nrf 2/MafK异源二聚体是肝癌发生过程中GST-P表达的重要正调控因子之一。我们发现，组蛋白乙酰转移酶，这是过表达的核提取物，从肝脏包括增生结节，作为一个辅因子的Nrf 2/MafK异源二聚体和诱导表达的GST-P。酵母中组蛋白变异体的功能分析：我们发现组蛋白变异体H2 A. Z在肝癌发生过程中被诱导。为了深入了解H2 A. Z的分子功能，我们在酿酒酵母中构建了一株H2 A. Z缺失菌株。H2A.Z缺失株对遗传毒性试剂敏感。此外，我们观察到对镍化合物的敏感性，这降低了所有四种组蛋白的乙酰化水平，增加了H2 A和H2 B的泛素化以及H3赖氨酸9的二甲基化，并揭示了镍毒性出现在由染色质重塑因子介导的H2 AZ掺入染色质中，而不是H2 AZ的乙酰化。少

Great effort has been directed towards understanding the mechanism of malignant transformation derived from genetic mutations. Nowadays, studies on epigenetic mutations in cancer are also required. In this project, we focused on epigenetics modulators (histone modification enzymes and histone variants), up-regulated during chemically induced hepatocarcinogenesis.1. Effect of over expression of histone modification enzymes on the malignant transformation.We identified histone modification enzymes, which induced during hepatocarcinogenesis by RT-PCR, DNA microarray, and Western blot analyses. One of them, histone acetyltransferase, regulated the transformation activity mediated by mutated ras oncogene. Histone deacetylase, one of other modulators, promoted anchorage independent growth in soft agarose.2. Effect of over expression of histone modification enzymes on expression of the tumor marker gene.Glutathione transferase placental form (GST-P) is specifically dramatically induced during … More hepatocarcinogenesis and recognized as a reliable tumor marker. Transcriptional factor Nrf2/MafK heterodimer is one of the most important positive regulators on GST-P expression during hepatocarcinogenesis. We revealed that one of histone acetyltransferase, which was over-expressed in nuclear extracts from livers including hyperplastic nodules, acted as a cofactor of Nrf2/MafK heterodimer and induced expression of GST-P.3. Functional analysis of the histone variant in yeast.We found that H2A.Z, one of histone variants, was induced during hepatocarcinogenesis. Tb gain insights of molecular function of H2A.Z, we generated a H2A.Z deletion strain in Saccharomyces cerevisiae. The H2A.Z deletion strain was sensitive to genotoxic reagents. Further, we observed the sensitivity to nickel compounds, which decrease acetylation levels of all four histones and increase ubiquitylation of H2A and H2B and dimethylation of H3 lysine 9, and revealed that the nickel toxicity appeared with the incorporation of H2AZ into chromatin mediated by the chromatin remodeling factor, but not acetylation of H2AZ. Less