SURGICAL STUDIES OF ONTOGENY, AGING AND THE GUT

个体发育、衰老和肠道的外科研究

• 批准号: 2052113
• 负责人: Bernard Mark Evers
• 金额: $ 11.9万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-01 至 1997-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2052113
• 关键词: DNA binding protein; DNA footprinting; aging; developmental genetics; embryo /fetus; gene expression; genetic promoter element; genetic regulatory element; genetic transcription; growth /development; immunocytochemistry; in situ hybridization; intestinal mucosa; jejunum; laboratory rat; messenger RNA; mutant; neurotensin; newborn animals; northern blottings; posttranscriptional RNA processing; radioimmunoassay; radiotracer; tissue /cell culture; tissue /cell preparation

Aging is characterized by an increase in the proliferative activity of gut mocosa which may contribute to development of pathological processes in the gut including cancer. Neurotensin (NT), a trophic gut peptide, stimulates gut mocosal growth in young and aged rats. In addition, NT mRNA levels increase with aging. The central hypothesis of this proposal is that NT gene expression in the gut is regulated in a temporal and tissue-specific fashion by mechanisms which involve transcriptional and post-transcriptional regulation; increases in NT levels may play a role in the increased proliferative activity found in gut mucosa with aging. To test the central hypothesis, we will employ the following specific aims: 1) We will further characterize the developmental regulation of NT in the gut. We will determine whether NT mRNA levels reflect actual NT peptide content by radioimmunoassay. We will next qualitatively determine the distribution of NT mRNA and peptide in gut mucosa. We will determine whether changes in NT mRNA levels in the jejunum and ileum are mediated by alterations in transcription and, if so, whether these changes occur by activation of a single or different promoters; 2) We will examine the increases in gut NT expression with aging. We will repeat our nuclear run-on studies to determine whether the increases of NT mRNA are the result of changes in transcription. If the increases in NT are not mediated by changes in transcription then we will determine the site (nucleus vs. cytoplasm) of increased NT mRNA. Finally, we will determine whether the increases of NT mRNA are associated with concomitant increases of NT peptide content and release; 3) We will delineate the sequences (cis-elements) essential for basal and tissue-specific expression of NT. We will then more precisely map the regulatory sequences of the NT gene using a series of mutant constructs. We will determine whether this 5' region of NT can confer activation to a minimal heterologous promoter. Next we will determine possible DNA-binding domains of the rat NT promoter. The long-term goal of this proposal is to determine whether NT plays a role in the increased proliferative activity that is found in gut mucosa with aging. The finding of an age-dependent increase of a growth factor that stimulates gut mucosal proliferation would be of potential clinical importance that may lead to a better understanding of the molecular mechanisms regulating the hyperproliferative changes that occur in the gut with age.

衰老的特征是增殖的增加 肠道Mocosa的活动可能有助于发展 肠道中的病理过程，包括癌症。 神经素 （NT），一种营养的肠肽，刺激肠道肠内的生长 年轻的老鼠。 另外，NT mRNA水平随着 老化。 该提议的中心假设是NT基因 肠道中的表达在时间上受到调节 通过涉及机制的组织特异性时尚 转录和转录后调节；增加 NT水平可能在增加的增殖活动中发挥作用 在肠道粘膜中发现。 为了检验中心假设，我们 将采用以下具体目标：1）我们将进一步 表征肠道中NT的发育调节。 我们将 确定NT mRNA水平是否反映了实际的NT肽含量 由放射免疫测定法。 接下来，我们将定性地确定 NT mRNA和肽在肠粘膜中的分布。 我们将 确定空肠和回肠中NT mRNA水平的变化是否变化 通过转录的改变来介导，如果是的话，是否 这些变化通过激活单个或不同而发生 发起人； 2）我们将检查肠道表达的增加 随着衰老。 我们将重复我们的核跑步研究以确定 NT mRNA的增加是否是变化的结果 转录。 如果NT的增加不是由变化介导的 在转录中，我们将确定位点（核Vs。 NT mRNA增加的细胞质）。最后，我们将确定是否 NT mRNA的增加与同时增加有关 NT肽含量和释放； 3）我们将描绘 基础和组织特异性必不可少的序列（顺式元素） NT的表达。 然后，我们将更精确地绘制监管 使用一系列突变构建体的NT基因序列。 我们 将确定NT的5'区域是否可以赋予激活 最小的异源启动子。 接下来我们将确定可能 大鼠NT启动子的DNA结合结构域。 该提议的长期目标是确定NT是否播放 在肠道中发现的增殖活性增加中的作用 粘膜衰老。 发现依赖年龄增加的发现 刺激肠粘膜增殖的生长因子将是 潜在的临床重要性可能导致更好 了解调节的分子机制 随着年龄的增长，肠道中发生的高增殖性变化。