Versatile model for conditional prostate gene expression

描述（由申请人提供）：越来越多的证据表明，生长因子和激素或其受体的表达和功能改变与前列腺疾病的病因有关。适当的动物模型的可用性将极大地促进确定在人类前列腺疾病中观察到的哪些基因表达变化与疾病的发生和进展有关。在哺乳动物系统中，目前唯一可行和实际的研究特定基因中功能突变的获得和丧失的影响的是小鼠。允许在小鼠基因组中添加或删除基因的系统的技术复杂性已经发展到现在可以产生几乎任何可以想象的基因改变的程度，从点突变到大规模删除。使用噬菌体p1 Cre-lox重组系统，这些变化可以以组织特异性的方式传递，前提是已经定义了能够指导Cre重组酶在适当组织中的表达的顺式作用元件。因此，开发和验证在前列腺上皮细胞中表达组成活性和诱导形式的Cre的转基因小鼠品系是一个高度优先考虑的问题。以前列腺限制性方式表达Cre的现有小鼠品系在大多数管腔上皮细胞中产生功能性Cre。尽管这些小鼠允许前列腺限制性基因操作，但这些小鼠中发生的高频率重组事件不允许模拟类似于可能发生在人类前列腺组织中的局灶性遗传变化。这里提出的工作目标是开发转基因小鼠菌株，这些小鼠在一定比例的前列腺上皮细胞中可重复表达Cre重组酶，从少数细胞到几乎所有细胞不等。我们建议产生表达Cre自然形式或可随意激活的诱导形式的小鼠品系。这一目标将通过产生在nkx-3.1顺式调控区控制下携带Cre基因的转基因小鼠品系来实现。Cre的功能将通过将nkx-3.1/ Cre转基因小鼠与小鼠报告品系交配来验证，其中β -半乳糖苷酶基因的激活依赖于Cre的切除。我们提出的转基因小鼠将对研究前列腺疾病发生或进展中任何基因的缺失或激活的影响非常有用。有了完整的人类基因组序列在手，我们准备开始前列腺疾病病因的系统分子解剖。我们在转基因小鼠中以组织特异性方式测试基因功能的能力将是这一过程的关键组成部分。

DESCRIPTION (provided by applicant): An increasing body of evidence points to alterations in the expression and function of growth factors and hormones or their receptors in the etiology of prostate disease. The availability of appropriate animal models would greatly facilitate 'efforts to determine which changes in gene expression observed in human prostate disease are relevant to disease initiation and progression. The only mammalian system where it is currently feasible and practical to examine the effects of both gain and loss of function mutations in specific genes is the mouse. The technical sophistication of the systems that permit the addition or deletion of genes to the mouse genome have progressed to the point where it is now possible to generate nearly any genetic alteration that can be envisioned, from point mutation to large-scale deletion. Using the bacteriophage P 1 Cre-lox recombination system, these changes can be imparted in a tissue-specific manner, provided that cis-acting elements capable of directing Cre recombinase expression in the appropriate tissue have been defined. The development and validation of transgenic mouse strains that express constitutively active and inducible forms of Cre in prostate epithelial cells is therefore a high priority. Existing strains of mice that express Cre in a prostate restricted manner produce functional Cre in the majority of luminal epithelial cells. Although these mice allow for prostate restricted manipulation of genes, the high frequency of recombination events that occur in these mice do not permit modeling of focal genetic changes similar to those that are likely to occur in human prostate tissue. The objective of the work proposed here is to develop strains of transgenic mice that reproducibly express the Cre recombinase in a percentage of prostate epithelial cells that varies from a few cells to nearly all. We propose to generate strains of mice that express either the natural form of Cre or an inducible form that can be activated at will. This goal will be achieved by generating strains of transgenic mice carrying Cre genes under the control of nkx-3.1 cis-regulatory regions. The function of Cre will be validated by mating the nkx-3.1/cre transgenic mice to a reporter strain of mice in which activation of a Beta-galactosidase gene is dependent on Cre excision. The transgenic mice we propose to generate will be extremely useful to study the effects of deletion or activation of any gene in the development or progression of prostate disease. With a complete sequence of the human genome in hand, we are poised to begin a systematic molecular dissection of prostate disease etiology. Our ability to test gene function in a tissue-specific manner in transgenic mice will be a critical component of that process.