Deschamps J, de Laaf R, Joosen L, Meijlink F, Destrée O
Proc Natl Acad Sci U S A. 1987 Mar;84(5):1304-8. doi: 10.1073/pnas.84.5.1304.
Mammalian homeobox-containing genes might play a role in embryonal pattern formation. In favor of this view is the recently reported expression of such genes during mouse embryogenesis [Manley, J. L. & Levine, M. S. (1985) Cell 43, 1-2]. The embryo-derived stem cells and in particular the pluripotent embryonal carcinoma (EC) cell lines are generally considered as a valid model of early mouse development. Homeobox-containing genes were shown to be expressed in differentiating EC cells. We have analyzed the expression of several of these genes in three EC cell lines triggered to differentiate by alternative treatments in the presence or in the absence of retinoic acid. In both types of conditions, C17S1 (clone 1003) and PCC7.S Aza R1 EC cells were induced to differentiate into mainly neurones, and PSA-1 EC cells were induced to differentiate into a large spectrum of tissue derivatives. Induction to high levels of expression of several homeobox-containing genes during differentiation occurs only in the presence of retinoic acid. Nonchemical treatment triggering differentiation does not lead to detectable expression of these genes. Accumulation to high amounts of homeobox-containing gene transcripts in these experiments seems to correlate with retinoic acid-induced EC cell differentiation rather than with EC cell differentiation as such.
哺乳动物中含同源框的基因可能在胚胎模式形成中发挥作用。支持这一观点的是最近报道的此类基因在小鼠胚胎发育过程中的表达情况[曼利，J. L. & 莱文，M. S.（1985年）《细胞》43卷，第1 - 2页]。胚胎来源的干细胞，尤其是多能胚胎癌（EC）细胞系，通常被视为早期小鼠发育的有效模型。研究表明含同源框的基因在分化的EC细胞中表达。我们分析了其中几个基因在三种EC细胞系中的表达情况，这三种细胞系在有或无视黄酸存在的情况下通过不同处理被触发分化。在这两种条件下，C17S1（克隆1003）和PCC7.S Aza R1 EC细胞被诱导主要分化为神经元，而PSA - 1 EC细胞被诱导分化为多种组织衍生物。只有在视黄酸存在的情况下，分化过程中几种含同源框的基因才会被诱导高水平表达。非化学处理触发分化不会导致这些基因的可检测表达。在这些实验中，含同源框的基因转录本大量积累似乎与视黄酸诱导的EC细胞分化相关，而非与EC细胞分化本身相关。
