The Role of Hox11 Paralogous Genes in Prostate Development

描述（由申请人提供）：靶向基因破坏研究已经证实Hox基因影响前列腺发育，但单突变动物的表型通常是温和的、多效性的、不完全渗透的。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。通过去除所有六个Hox11旁系基因的功能拷贝，我们产生了在发育中的前列腺有严重缺陷的动物。初步数据表明，三重突变动物显示出非常断裂的芽模式，而来自E18.5泌尿生殖窦的前列腺芽的前叶和背外侧叶，它们没有分支或发育过这个阶段。幸存的四等位基因动物在成年后表现出这些缺陷的不完全外显性。结合先前关于Hox10和Hox13旁系群的单突变体的数据，似乎前列腺的发育是响应来自AbdB Hox基因的正向模式信号，其中Hox10基因模式主要是前列腺前部，Hox11基因模式主要是前列腺背外侧，Hox13基因模式主要是前列腺腹侧。这些缺陷的性质对理解这一器官系统的发育以及开始理解Hox基因在疾病中的潜在作用具有重要意义。实验室结果表明，Hox11蛋白与Pax2和Eya1一起形成一个调节复合体，共同激活下游基因，如肾脏中的Six2和Gdnf。这两个基因也在发育中的前列腺中表达，我们的初步数据显示Gdnf在发育中的前列腺中起作用，支持这一途径在前列腺发育中的保存。我们还在Hox11的旁系基因中设计了新的结构，产生零等位基因，但也表达来自内源位点的荧光融合蛋白。此外，由于Hox11菌落中的三突变体和高等位基因突变体由于肾脏发育不足而在新生儿阶段死亡，我们已经制定了允许我们通过早期导管形态发生继续前列腺生长的培养条件。在培养实验中使用我们新生成的荧光等位基因将允许在早期前列腺器官发生过程中实时成像Hox表达。我们假设Hox11的旁系基因参与前列腺背外侧的模式，并且它们的间质表达对于前列腺这一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.