Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America.
PLoS One. 2012;7(2):e32085. doi: 10.1371/journal.pone.0032085. Epub 2012 Feb 21.
The magnocellular neurons (MCNs) in the hypothalamus selectively express either oxytocin (OXT) or vasopressin (AVP) neuropeptide genes, a property that defines their phenotypes. Here we examine the molecular basis of this selectivity in the OXT MCNs by stereotaxic microinjections of adeno-associated virus (AAV) vectors that contain various OXT gene promoter deletion constructs using EGFP as the reporter into the rat supraoptic nucleus (SON). Two weeks following injection of the AAVs, immunohistochemical assays of EGFP expression from these constructs were done to determine whether the EGFP reporter co-localizes with either the OXT- or AVP-immunoreactivity in the MCNs. The results show that the key elements in the OT gene promoter that regulate the cell-type specific expression the SON are located -216 to -100 bp upstream of the transcription start site. We hypothesize that within this 116 bp domain a repressor exists that inhibits expression specifically in AVP MCNs, thereby leading to the cell-type specific expression of the OXT gene only in the OXT MCNs.
下丘脑的大细胞神经元（MCN）选择性地表达催产素（OXT）或血管加压素（AVP）神经肽基因，这种特性定义了它们的表型。在这里，我们通过立体定向微注射含有各种 OXT 基因启动子缺失构建体的腺相关病毒（AAV）载体，使用 EGFP 作为报告基因，将其注入大鼠视上核（SON），来研究 OXT MCN 中这种选择性的分子基础。在注射 AAV 两周后，通过免疫组织化学检测这些构建体的 EGFP 表达，以确定 EGFP 报告基因是否与 MCN 中的 OXT 或 AVP 免疫反应性共定位。结果表明，调节 SON 中细胞类型特异性表达的 OT 基因启动子的关键元件位于转录起始位点上游的-216 至-100bp 处。我们假设在这个 116bp 区域内存在一个阻遏物，它特异性地抑制 AVP MCN 中的表达，从而导致 OXT 基因仅在 OXT MCN 中特异性表达。
