Hiroi T, Hayashi-Kobayashi N, Nagumo S, Ino M, Okawa Y, Aoba A, Matsui H
Radioisotope Research Institute, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan.
Biochem Biophys Res Commun. 2001 Nov 30;289(2):337-44. doi: 10.1006/bbrc.2001.5979.
The human serotonin-4 (5-HT(4)) receptor gene expression is highly regulated in various tissues. We isolated the human 5-HT(4) receptor gene containing the 5'-flanking region and characterized its promoter. By 5'-RACE (5'-rapid amplification of the cDNA ends) and inverse PCR, multiple transcription initiation sites were identified. The most 5' one (assigned to +1) was 5135 bp upstream to the translation start site. The 500-bp 5'-flanking region contained potential binding sites for transcription factor Sp-1, AP-2, AP-4, and GATA. However, this region lacked TATA- and CAAT-boxes. Transient transfection analyses in human choriocarcinoma T3M-3 (5-HT(4) receptor-positive) and HepG2 (5-HT(4) receptor-negative) cells revealed that the region (-210 to -105) is necessary for the basic and cell-type specific 5-HT(4) receptor gene expression. In addition, untranslated exon 1 contained negative (+112 to +182) as well as positive (+1 to +111) modulators, indicating that exon 1 plays a regulatory role in the 5-HT(4) receptor gene expression.
人类5-羟色胺4（5-HT(4)）受体基因在各种组织中受到高度调控。我们分离出包含5'侧翼区的人类5-HT(4)受体基因，并对其启动子进行了表征。通过5'-RACE（5'-cDNA末端快速扩增）和反向PCR，鉴定出多个转录起始位点。最靠近5'端的一个（定为+1）位于翻译起始位点上游5135 bp处。500 bp的5'侧翼区包含转录因子Sp-1、AP-2、AP-4和GATA的潜在结合位点。然而，该区域缺乏TATA盒和CAAT盒。在人绒毛膜癌T3M-3（5-HT(4)受体阳性）和HepG2（5-HT(4)受体阴性）细胞中进行的瞬时转染分析表明，（-210至-105）区域对于5-HT(4)受体基因的基础表达和细胞类型特异性表达是必需的。此外，非翻译外显子1包含负性（+112至+182）以及正性（+1至+111）调节因子，表明外显子1在5-HT(4)受体基因表达中起调节作用。
