Regulatory mechanism of hormone gene expression in the anterior pituitary gland in birds

鸟类PRL在脑垂体前叶中的调节机制与哺乳动物PRL完全不同，具有独特性。本研究的目的是克隆鸡PREB并比较其在胚胎发生过程中各组织中mRNA的表达水平。鸡的PREB cDNA与人类和大鼠的PREB cDNA相似度为70%。PREB mRNA表达呈组织依赖性。有趣的是，胚胎发生过程中未观察到垂体前叶PREB mRNA水平的变化。这些结果表明PREB蛋白参与了多种基因的调控。此外，在胚胎发生后期，PREB涉及PRL基因的激活而不是mRNA水平的增加。

The regulatory mechanism of bird PRL in the anterior pituitary gland is unique and completely different to that of mammalian PRL. The aims of this study were cloning of chicken PREB and comparison of levels of mRNA expression in the various tissues during embryogenesis. Chicken PREB cDNA shows 70% similarity to human and rat PREB cDNAs. The levels of PREB mRNA showed tissue dependent manner. Interestingly, the changes of levels of PREB mRNA had not been observed in the anterior pituitary gland during embryogenesis. These results suggest that PREB protein participate regulation of various gene. Furthermore, PREB involves activation of PRL gene rather than increase of mRNA levels during late stage of embryogenesis.