Jolivet G, L'Hotte C, Pierre S, Tourkine N, Houdebine L M
Unité de Différenciation Cellulaire, Laboratoire de Biologie Cellulaire et Moléculaire, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
FEBS Lett. 1996 Jul 8;389(3):257-62. doi: 10.1016/0014-5793(96)00598-4.
The rabbit alphas1-casein gene contains a distal prolactin-dependent enhancer 3442-3285 bp 5' to the site of initiation of transcription. We have reported previously that four DNA/protein-binding sites (F1-F4) are located within this distal enhancer. We now show that one of this binding site (the F4 site) binds in vitro a MGF/STAT5-like factor. The functional importance of the F4 site was estimated by cotransfection of CHO cells with a chimeric gene containing or not the F4 sequence linked to the (-391/+1774)CAT gene and a plasmid encoding the rabbit mammary prolactin receptor. The F4 site is necessary for maximal response, of the enhancer to prolactin. However, this site has to be associated to the Fl-F3 fragment. It can be replaced by a genuine MGF/STAT5-binding site. A mutational analysis indicates that F4 and F1 sites are simultaneously involved to confer a high prolactin sensitivity.
兔αs1-酪蛋白基因在转录起始位点5'端3442 - 3285 bp处含有一个远端催乳素依赖性增强子。我们之前报道过，在这个远端增强子内有四个DNA/蛋白质结合位点（F1 - F4）。我们现在表明，其中一个结合位点（F4位点）在体外能结合一种MGF/STAT5样因子。通过将含有或不含有与（-391/+1774）CAT基因相连的F4序列的嵌合基因与编码兔乳腺催乳素受体的质粒共转染CHO细胞，评估了F4位点的功能重要性。F4位点对于增强子对催乳素的最大反应是必需的。然而，这个位点必须与F1 - F3片段相关联。它可以被一个真正的MGF/STAT5结合位点取代。突变分析表明，F4和F1位点同时参与赋予高催乳素敏感性。
