The Role of Hox11 Paralogous Genes in Prostate Development

描述(申请人提供)：有针对性的基因中断研究已经证实HOX基因影响前列腺发育，但单个突变动物的表型通常是温和的、多效性的和不完全穿透的。由于这些缺陷的性质，很难确定HOX基因在发育中的前列腺中的遗传功能。通过移除Hox11基因的所有六个功能副本，我们产生了发育中的前列腺严重缺陷的动物。初步数据表明，三个突变的动物表现出一种非常混乱的花蕾模式，虽然E18.5泌尿生殖窦的前列腺芽的前叶和背外侧叶，但它们不会在这个阶段之后分支或发育。存活下来的四个等位基因的动物成年后对这些缺陷表现出不完全的外显。结合之前关于Hox10和Hox13近缘组中单个突变体的数据，似乎前列腺的发育是对AbdB Hox基因前后模式信号的响应，其中Hox10基因模式前前列腺，Hox11基因模式主要在前列腺背侧，Hox13基因模式主要模式在前列腺腹侧。这些缺陷的性质对于理解这一器官系统的发育以及开始了解HOX基因在疾病中的潜在作用具有重要的意义。实验室的结果表明，Hox11蛋白与Pax2和Eya1一起形成一个调节复合体，共同激活肾脏中的下游基因，如SIX2和GDNF。这两个基因也在发育中的前列腺中表达，我们的初步数据表明，GDNF在发育中的前列腺中发挥功能，支持在前列腺发育中保护这一途径。我们还在Hox11平行基因中设计了新的结构，这些结构产生零等位基因，但也表达来自内源基因座的荧光融合蛋白。此外，由于Hox11群体中的三个突变和高等位基因突变由于肾脏发育不足而在新生儿阶段死亡，我们已经制定了培养条件，使我们能够通过早期导管形态发生继续前列腺生长。在培养实验中使用我们新产生的荧光等位基因将允许实时成像早期前列腺器官发生过程中HOX的表达。我们推测，Hox11类基因有助于形成前列腺背外侧的模式，并且它们的间质表达对于这一发育中的前列腺区域的分支、形态发生和生长是必要的。这些研究将为前列腺发育中HOX调控的遗传和分子基础提供关键的见解。

DESCRIPTION (provided by applicant): Targeted gene disruption studies have confirmed that Hox genes affect prostate development, but phenotypes of single mutant animals have been generally mild, pleiotropic, and incompletely penetrant. Because of the nature of these defects, it has been difficult to determine the genetic function of Hox genes in the developing prostate. By removing all six functional copies of the Hox11 paralogous genes, we have generated animals with profound defects in the developing prostate. Preliminary data suggests that triple mutant animals display a very disrupted bud pattern and, while the anterior and dorsolateral lobes of the prostate bud from E18.5 urogenital sinuses, they do not branch or develop past this stage. Surviving four-allele animals show incomplete penetrance of these defects as adults. Together with previous data on single mutants in the Hox10 and Hox13 paralogous groups, it appears that the prostate develops in response to anteroposterior patterning signals from the AbdB Hox genes, with Hox10 genes patterning the anterior prostate, Hox11 genes patterning primarily the dorsolateral prostate and Hox13 genes patterning primarily the ventral prostate. The nature of these defects have important implications for understanding the development of this organ system, as well as beginning to understand potential roles for Hox genes have in disease. Results in the laboratory suggest that Hox11 proteins, together with Pax2 and Eya1, form a regulatory complex that, together can activate downstream genes, such as Six2 and Gdnf in the kidney. Both of these genes are also expressed in the developing prostate, and our preliminary data shows Gdnf functions in the developing prostate, supporting the conservation of this pathway in prostate development. We have also engineered new constructs in the Hox11 paralogous genes that produce null alleles, but also express fluorescently fusion proteins from the endogenous loci. Additionally, as triple mutant and high-allele mutants in the Hox11 colony die at newborn stages due to insufficient kidney development, we have worked out culture conditions that allow us to continue prostatic growth through early ductal morphogenesis. Using our newly generated fluorecent alleles in culture experiments will allow real-time imaging of Hox expression during early prostate organogenesis. We hypothesize that Hox11 paralogous genes contribute to patterning the dorsolateral prostate and their mesenchymal expression is necessary for branching morphogenesis and growth of this region of the developing prostate. These studies will provide key insights into the genetic and molecular basis of Hox regulation in prostate development.