Mechanism of P73-dependent Tumor Suppression

项目摘要/摘要 P73是抑癌基因p53家族的一员，由两个启动子表达：上游启动子 产生TAp73的P1启动子和产生ΔNp73的下游P2启动子。另外， P73通过外显子11-13之间的选择性剪接表达为六种亚型(α、β、伽马、β、β、Zeta)。作为一名 转录因子，我们和其他人发现TAp73含有一个类似于第一个的激活结构域 P53中的激活结构域(AD1)。我们还在ΔNp73中发现了一个独特的激活结构域。因此， Tap73和Δnp73能够诱导一组不同的靶基因。与ITS一致 转录活性，缺乏TAp73的小鼠容易发生自发性肿瘤并加速衰老 然而，Δnp73基因缺失的小鼠更容易出现神经缺陷。然而，与TA和ΔN相比 对于p73C末端的异构体及其在体内的活性，人们知之甚少。现在，通过使用 CRISPR-Cas9方法在细胞系和小鼠中删除p73基因的一个或多个外显子，我们能够 目的：系统研究p73 C末端异构体在体内外的作用。我们的初步数据 结果表明，不同的p73C末端亚型具有不同的活性。因此，我们假设每个 P73 C末端亚型在抑制肿瘤和延长寿命方面具有独特的功能。为了测试这一点，我们将 测定：(1)细胞生长和分化中的C-末端异构体特异性活性；(2)C-末端 异构体特异性活性在肿瘤抑制和长寿中的作用；(3)C末端异构体特异性效应 P53基因缺陷或突变型p53R270H敲门小鼠肿瘤发生的研究。

Project Summary/Abstract p73, a member of the p53 family of tumor suppressors, is expressed from two promoters: the upstream P1 promoter that produces TAp73 and the downstream P2 promoter that produces ΔNp73. Additionally, p73 is expressed as six isoforms (alpha, Beta, gamma, delta, epsilon, zeta) through alternative splicing between exon 11-13. As a transcription factor, we and others showed that TAp73 contains an activation domain similar to the first activation domain (AD1) in p53. We also identified a unique activation domain in ΔNp73. Thus, TAp73 and ΔNp73 are capable of inducing a distinct set of target genes. Consistent with its transcriptional activity, mice deficient in TAp73 are prone to spontaneous tumors and accelerated aging whereas mice deficient in ΔNp73 are prone to neurological defects. However, compared to TA and ΔN isoforms, very little is known about p73 C-terminal isoforms and their activities in vivo. Now, by using CRISPR-cas9 method to delete one or more exons in the p73 gene in cell lines and in mice, we are able to systematically study the role of p73 C-terminal isoforms in vitro and in vivo. Our preliminary data showed that various p73 C-terminal isoforms have distinct activities. Thus, we hypothesize that each p73 C-terminal isoform has a unique function in tumor suppression and longevity. To test this, we will determine: (1) C-terminal isoform-specific activities in cell growth and differentiation; (2) C-terminal isoform-specific activities in tumor suppression and longevity; (3) C-terminal isoform-specific effects on tumorigenesis in p53-deficient or mutant p53R270H knockin mice.