Identification of Alternative Hif-1a Dimerization artners in Arnt (Hifljff)-null

p53肿瘤抑制因子家族成员（p53、p63和p73）在细胞功能、动物免疫和肿瘤发生中起关键作用。 发展和肿瘤抑制。特别是P63，已知对发育至关重要。 表皮p63 mRNA可以通过两个启动子转录，产生不同的N-末端， 确定它们是否包含（TA）或缺乏（DN）完整的激活域。Tap 63最近在 提出在胚胎发生过程中指导角质形成细胞定型，而DNp 63是主要亚型 在具有高增殖潜能的正常和肿瘤性角质形成细胞中均发现。由于分子 p63功能的潜在机制在很大程度上仍然是未知的，我们建议通过以下方法进行研究 方法。 首先，我们利用人角质形成细胞cDNA文库进行了酵母双杂交筛选 并鉴定了4种新的p63相互作用伙伴。我们目前正在研究生物功能， 由p63及其结合伴侣介导。第二，p63与其家族成员之间的串扰 (p53和TAp 63）将被调查。已经发现DNp 63，角质形成细胞中主要的p63同种型， 在报告基因测定中，可以抑制p53和TAp 63的活性。我们计划研究DNp 63是否可以 在体内抑制p53和TAp 63的活性，以及这种活性是否受p63-bidning的调节。 proteins.第三，我们将在角质形成细胞中寻找p63结合的直接靶基因， 免疫沉淀方案和DNA微阵列分析。一旦这些基因被识别出来，p63 （连同其结合蛋白）调节它们，以及它们在角质形成细胞中的作用将进一步 追求。

Members of the p53 tumor suppressor family (p53, p63 and p73) play critical roles in cell function, animal development and tumor suppression. P63 in particular is known to be crucial for the development of the epidermis. p63 mRNAs can be transcribed through two promoters to produce different N-termini that determine whether they contain (TA) or lack (DN) a full activation domain. TAp63 has been recently proposed to direct keratinocyte commitment during embryogenesis, while DNp63 is the dominant isoform found in both normal and neoplastic keratinocytes with high proliferative potential. Since the molecular mechanisms underlying p63 functions are still largely unknown, we propose to study this by the following approaches. First, we have performed exhaustive yeast two hybrid screening using a human keratinocyte cDNA library and have identified 4 novel p63 interactive partners. We are currently investigating biological functions that are mediated by p63 and its binding partners. Second, the cross talk between p63 and its family members (p53 and TAp63) will be investigated. It has been found that DNp63, the major p63 isoform in keratinocytes, can suppress the activity of p53 and TAp63 in reporter assays. We plan to examine whether DNp63 can inhibit the activity of p53 and TAp63 in vivo, and whether such activity is regulated by the p63-bidning proteins. Third, we will search for direct target genes bound by p63 in keratinocytes using both chromosome immunoprecipitation protocol and DNA microarray analysis. Once those genes are identified, how p63 (together with its binding proteins) regulates them and what their roles in keratinocytes will be further pursued.