Venkatesh B, Si-Hoe S L, Murphy D, Brenner S
Molecular Genetics Laboratory, Institute of Molecular and Cell Biology, National University of Singapore, 15, Lower Kent Ridge Road, Singapore 119076, USA.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12462-6. doi: 10.1073/pnas.94.23.12462.
We have asked whether comparative genome analysis and rat transgenesis can be used to identify functional regulatory domains in the gene locus encoding the hypothalamic neuropeptides oxytocin (OT) and vasopressin. Isotocin (IT) and vasotocin (VT) are the teleost homologues of these genes. A contiguous stretch of 46 kb spanning the Fugu IT-VT locus has been sequenced, and nine putative genes were found. Unlike the OT and vasopressin genes, which are closely linked in the mammalian genome in a tail-to-tail orientation, Fugu IT and VT genes are linked head to tail and are separated by five genes. When a cosmid containing the Fugu IT-VT locus was introduced into the rat genome, we found that the Fugu IT gene was specifically expressed in rat hypothalamic oxytocinergic neurons and mimicked the response of the endogenous OT gene to an osmotic stimulus. These data show that cis-acting elements and trans-acting factors mediating the cell-specific and physiological regulation of the OT and IT genes are conserved between mammals and fish. The combination of Fugu genome analysis and transgenesis in a mammal is a powerful tool for identifying and analyzing conserved vertebrate regulatory elements.
我们探讨了比较基因组分析和大鼠转基因技术是否可用于鉴定编码下丘脑神经肽催产素（OT）和加压素基因座中的功能调控域。异催产素（IT）和加压催产素（VT）是这些基因的硬骨鱼同源物。已对跨越河豚IT-VT基因座的46 kb连续片段进行了测序，发现了9个推定基因。与在哺乳动物基因组中以尾对尾方向紧密连锁的OT和加压素基因不同，河豚IT和VT基因头对尾相连，且被5个基因隔开。当将包含河豚IT-VT基因座的黏粒导入大鼠基因组时，我们发现河豚IT基因在大鼠下丘脑催产素能神经元中特异性表达，并模拟了内源性OT基因对渗透压刺激的反应。这些数据表明，介导OT和IT基因细胞特异性和生理调控的顺式作用元件和反式作用因子在哺乳动物和鱼类之间是保守的。河豚基因组分析与哺乳动物转基因技术相结合是鉴定和分析保守脊椎动物调控元件的有力工具。
