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

鸟类催乳素在垂体前叶的调节机制是独特的，与哺乳动物催乳素的调节机制完全不同。本研究的目的是克隆鸡PREB基因，并比较胚胎发生过程中不同组织中PREB基因的表达水平。鸡PREB cDNA与人和大鼠的PREB cDNA有70%的相似性。PREB mRNA表达水平呈组织依赖性。在胚胎发育过程中，未观察到垂体前叶PREB mRNA水平的变化。提示PREB蛋白参与多种基因的调控。此外，PREB涉及PRL基因的激活，而不是在胚胎发生后期的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.