THE HORMONAL CONTROL OF FETAL GROWTH

这一建议是基于这样的假设：胰岛素样生长 因子(IGF-I和IGF-II)对调节胚胎和 胎儿生长发育。我们推测IGFS、IGF受体， 和IGF结合蛋白(IGFBPs)从早期就开始表达 胚胎发生，以及发病时间和表达的控制 这些蛋白质因细胞成熟阶段的不同而不同。 此外，由于IGFS具有不同的生物效应，我们认为 所有IGF在子宫内的作用还没有被定义。这样做的目的是 因此，建议确定IGF、IGF受体植入的时间 和IGFBP的表达，阐明宫内IGFS的调控因素； 并定义IGF行动和重要的行动机制 发展。具体地说，我们将确定 种植前胰岛素样生长因子、胰岛素样生长因子受体和胰岛素样生长因子结合蛋白的表达 大鼠和小鼠通过新生生命的胚胎发生(Spec.目标1)。至 明确胰岛素样生长因子、胰岛素样生长因子受体和胰岛素样生长因子结合蛋白在胰岛素抵抗中的表达 子宫和新生儿发育(规范。目标2)，我们将评估这些因素 在胚胎癌细胞系中调节体外表达，并在 培养胎鼠和新生大鼠成纤维细胞。我们还将在体内进行评估 胰岛素样生长因子、胰岛素样生长因子受体和胰岛素样生长因子相关蛋白在胎鼠组织中的表达 受到导致胎儿宫内发育迟缓的干扰 以及给药被发现改变其表达的物质 这些蛋白质在体外。确定刺激IGF的因素 转录(规范目的3)，我们将研究基因的表达调控 连接IGF5‘基因组侧翼元件和报告基因的融合基因 稳定表达的培养细胞和转基因小鼠。使用多个 旨在改变IGF表达的转基因，我们将在子宫中研究 以及IGFS在培养的稳定表达细胞中的作用机制 (规格。目标4)和转基因小鼠(Spec.目标5)。调查IGF 行动，我们将：a)在胚胎和胎儿中创造IGF-I的表达- 使用融合的转基因不能正常表达IGF-I的衍生细胞 金属硫蛋白启动子或mIGF-II基因组5‘侧翼 IGF-IA基因的区域，b)在子宫内产生IGF-I在 利用MIGF-II 5‘侧翼IGFS和In融合的转基因小鼠 利用表达反义IGF转录本的融合基因转基因小鼠 或专门切割IGF转录本的核酶。要检查 IGF-I的作用机制，我们将：a)检查IGF-I的变化 胰岛素样生长因子受体和胰岛素样生长因子结合蛋白的表达 上述IGF表达的变化，b)检测IGF-I的潜在自分泌 使用转基因表达突变的IGF-I分子而不是 分泌是因为它们有氨基酸(KDEL)尾部序列 以内质网为目标，或者因为它们缺乏信号肽， C)通过研究确定IGFBP-1的表达对IGF作用的影响 培养细胞和转基因小鼠表达编码基因 HBP-1和反义HBP-1转录本(Spec.目标6)。

This proposal is based on the hypothesis that the Insulin-like Growth Factors (IGF-I and IGF-II) are essential to the regulation of embryonic and fetal growth and development. We postulate that the IGFs, IGF receptors, and IGF binding proteins (IGFBPs) are expressed from early in embryogenesis, and that the time of onset and control of expression of these proteins differs depending on the stage of cellular maturation. Furthermore, because the IGFs have diverse biologic effects, we believe that all IGF in utero actions have not been defined. The goals of this proposal therefore, are to determine the time of inset of IGF, IGF receptor and IGFBP expression; to elucidate the factors that regulate IGFs in utero; and to define IGF actions and mechanisms of action important to development. Specifically, we will determine the ontogeny and sites of expression of the IGFs, IGF receptors and IGFBPs from pre-implantation embryogenesis through neonatal life in rats and mice (Spec. Aim 1). To define the regulation IGF, IGF receptor and IGFBP expression during in utero and neonatal development (Spec. Aim 2), we will assess the factors that modulate in vitro expression in embryonal carcinoma cell lines and in cultured fetal and neonatal rat fibroblasts. We also will evaluate in vivo expression of IGFs, IGF receptors and IGFBPs in tissues of fetal rats subjected to perturbations that result in intrauterine growth retardation and to the administration of substances found to alter the expression of these proteins in vitro. To determine the factors that stimulate IGF transcription (Spec. Aim 3), we will study the regulation of expression of fusion genes linking IGF 5' genomic flanking elements to reporter genes in stably transfected cultured cells and transgenic mice. Using a number of transgenes designed to alter IGF expression, we will study in utero actions and mechanisms of action of IGFs in cultured stably transfected cells (Spec. Aim 4) and transgenic mice (Spec. aim 5). To investigate IGF actions, we will: a) create IGF-I expression in embryonic and fetal- derived cells that do not normally express IGF-I using transgenes that fuse either the metallothionein promoter or the mIGF-II genomic 5' flanking region to an IGF-IA gene, b) generate in utero IGF-I overexpression in transgenic mice using the fusion of MIGF-II 5' flanking IGFs and in transgenic mice using fusion genes that express anti-sense IGF transcripts or ribozymes that specifically cleave IGF transcripts. To examine the mechanisms of IGF-I's actions, we will: a) examine changes in the expression of IGF receptors and IGFBPs as a consequence of each of the above alterations in IGF expression, b) test IGF-I's potential autocrine actions, using transgenes expressing mutant IGF-I molecules that are not secreted either because they have amino acid (KDEL) trailer sequence targeting the endoplasmic reticulum or because they lack a signal peptide, and c) determine the effect of IGFBP-1 expression on IGF actions by study of cultured cells and transgenic mice made to express transgenes encoding hBP-1 and an anti-sense hBP-1 transcript (Spec. Aim 6).