REGULATION OF ERYTHROPOIETIN GENE EXPRESSION IN FETUS

胎儿和成人的红细胞生成是由激素调节的 促红细胞生成素(EPO)在成人中，促红细胞生成素是在肾脏产生的。促红细胞生成素 据信主要由肝脏产生，其中 只有在怀孕后期，肾脏才成为一个重要的来源。然而， 通过分子技术，EPO基因的高水平表达 在整个妊娠过程中发现在胎儿肾脏中，而EPO基因 在胎儿肝脏中的表达水平较低。此外，新的研究表明 胎盘是胎儿组织，会产生促红细胞生成素。这些因素 刺激EPO产生的主要原因是缺氧和贫血。然而， 低氧和贫血对促红细胞生成素基因影响的特点 在胎儿中的表达还没有被检测到。建议进行的研究 旨在探索EPO基因表达的调节和 绵羊胎儿血浆促红细胞生成素浓度与生理学变化的关系 和分子方法。具体目标1将建立常态 促红细胞生成素基因在胎盘、胎肝和肾脏中的表达模式 从孕期50天到足月(150天)。北方人的技艺 竞争性逆转录聚合酶链法分析 反应将用于EPO信使RNA的定量 (M RNA)。表达EPO mRNA的细胞类型的定位 和蛋白质将通过原位的方法完成 杂交和免疫组织化学。假设是每一个 组织在怀孕期间表现出不同的模式。特定目标2将 探讨母体低氧所致胎儿缺氧对胎儿生长发育的影响 胎儿肾脏、肝脏和胎盘中EPO mRNA丰度的研究 妊娠100至150天。假设EPO基因表达 在胎盘和胎儿肾脏中的增强作用比在胎盘和胎儿肾脏中的增强更大 肝脏。特定目标3将探索EPO基因表达对 胎龄100~150天胎儿贫血所致缺氧 怀孕了。假说是胎儿贫血诱导EPO mRNA在 肾脏和肝脏，但不是胎盘。我们的总体假设是 胎盘、胎肝和胎肾表达EPO的差异 跨孕期和低氧诱导EPO基因表达 在每个组织中取决于缺氧的类型。这些研究是 意义重大，因为它们可以显著提高我们的理解 促红细胞生成素和红细胞在胎儿中的产生的调节 重要的是因为它们可以帮助改善诊断和治疗 患有贫血和/或溶血性疾病的人类胎儿和新生儿， 从而改善围产儿结局。

Erythropoiesis in the fetus and adult is regulated by the hormone erythropoietin (Epo). In the adult, Epo is produced in the kidney. Epo in the fetus is believed to be produced mainly by the liver, with the kidneys becoming an important source only late is gestation. However, with molecular techniques, high levels of Epo gene expression are found in the fetal kidney throughout gestation whereas Epo gene expression in the fetal liver is low. Further, new studies suggest that the placenta, which is fetal tissue, produces Epo. The factors which stimulate Epo production are hypoxia and anemia. However, the characteristics of the hypoxic and anemic effects on Epo gene expression have not been examined in the fetus. The proposed studies are designed to explore the regulation of Epo gene expression and plasma Epo concentration in the ovine fetus by combining physiological and molecular approaches. Specific Aim 1 will establish the normal patterns of Epo gene expression in placenta, fetal liver and kidneys from 50 days gestation to term (150 days). The techniques of Northern analysis and competitive reverse transcription-polymerase chain reaction will be used for the quantification of Epo messenger RNA (mRNA). The localization of the cell types which express Epo mRNA and protein will be accomplished by the methods of in situ hybridization and immunohistochemistry. The hypothesis is that each tissue displays different patterns across gestation. Specific Aim 2 will explore the effects of fetal hypoxia induced by maternal hypoxemia on Epo mRNA abundance in kidney, liver and placenta of fetuses from 100 to 150 days gestation. The hypothesis is that Epo gene expression will be enhanced more in the placenta and fetal kidney than in the liver. Specific Aim 3 will explore Epo gene expression responses to hypoxia induced by fetal anemia in fetuses from 100-150 days gestation. The hypothesis is that fetal anemia induces Epo mRNA in the kidney and liver but not the placenta. Our overall hypothesis is that the placenta, fetal liver and kidney differentially express Epo across gestation and that the hypoxic induction of Epo gene expression in each tissue depends on the type of hypoxia. These studies are significant because they could significantly improve our understanding of the regulation of Epo and red cell production in the fetus and are important because they could help improve the diagnosis and treatment of human fetuses and neonates with anemia and/or hemolytic disease, thereby improving perinatal outcome.