Berghorn K A, Clark P A, Encarnacion B, Deregis C J, Folger J K, Morasso M I, Soares M J, Wolfe M W, Roberson M S
Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
J Endocrinol. 2005 Aug;186(2):315-23. doi: 10.1677/joe.1.06217.
Distal-less 3 (Dlx3) is a homeobox factor that functions as a placental-specific transcriptional regulator. Dlx3 null mice (-/-) have compromised placental development and do not survive in utero past embryonic day (E) 9.5. The current studies were undertaken to examine the expression of Dlx3 in mouse placenta during gestation, and to determine whether Dlx3 was involved in placental progesterone production. Dlx3 was not detectable at E8.5 but was detected in E9.5 placenta with continuing but diminished expression through E15.5. Dlx3 immuno-localization was restricted to the labyrinth, was nuclear and was found in cytokeratin-positive cells. Previous studies in choriocarcinoma cell lines support the conclusion that Dlx3 is required for expression of 3'-hydroxysteroid dehydrogenase VI (3betaHSD VI), an obligate enzyme in the production of progesterone by trophoblast giant cells. In a rat trophoblast stem cell line (Rcho-1), Dlx3 expression was non-detectable in Rcho-1 cells induced to differ-entiate using mitogen withdrawal. In vitro progesterone production in placental cultures and 3betaHSD VI mRNA from Dlx3 (+/+), (+/-) and (-/-) mice were equivalent. In situ hybridization for 3betaHSD VI revealed mRNA expression restricted to trophoblast giants cells with no detectable expression in the labyrinth suggesting that Dlx3 and 3betaHSD VI were not colocalized within the placenta. These studies support the conclusion that Dlx3 protein expression is restricted to the labyrinth region of the murine placenta into late gestation and that Dlx3 does not appear to be expressed in trophoblast giant cells. Further, loss of Dlx3 was not correlated with synthesis of progesterone from E9.5 mouse placentas.
远端缺失3（Dlx3）是一种同源盒因子，作为胎盘特异性转录调节因子发挥作用。Dlx3基因敲除小鼠（-/-）的胎盘发育受损，在胚胎期第9.5天（E9.5）后无法在子宫内存活。当前的研究旨在检测妊娠期小鼠胎盘中Dlx3的表达，并确定Dlx3是否参与胎盘孕酮的产生。在E8.5时未检测到Dlx3，但在E9.5的胎盘中检测到，其表达持续存在，但在E15.5时表达减弱。Dlx3免疫定位仅限于迷路区，呈核定位，且存在于细胞角蛋白阳性细胞中。先前在绒毛膜癌细胞系中的研究支持以下结论：Dlx3是滋养层巨细胞产生孕酮过程中必需的3'-羟基类固醇脱氢酶VI（3βHSD VI）表达所必需的。在大鼠滋养层干细胞系（Rcho-1）中，使用有丝分裂原撤除诱导分化的Rcho-1细胞中未检测到Dlx3表达。来自Dlx3（+/+）、（+/-）和（-/-）小鼠的胎盘培养物中的体外孕酮产生以及3βHSD VI mRNA水平相当。3βHSD VI的原位杂交显示，mRNA表达仅限于滋养层巨细胞，在迷路区未检测到表达，这表明Dlx3和3βHSD VI在胎盘中并非共定位。这些研究支持以下结论：Dlx3蛋白表达在妊娠后期仅限于小鼠胎盘的迷路区，且Dlx3似乎不在滋养层巨细胞中表达。此外，Dlx3的缺失与E9.5小鼠胎盘孕酮的合成无关。
