Allen N D, Cran D G, Barton S C, Hettle S, Reik W, Surani M A
Department of Molecular Embryology, Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, UK.
Nature. 1988 Jun 30;333(6176):852-5. doi: 10.1038/333852a0.
Embryonic development entails a well defined temporal and spatial programme of gene expression, which may be influenced by active chromosomal domains. These chromosomal domains can be detected using transgenes which integrate randomly throughout the genome, as their expression can be affected by chromosomal position. Position effects are probably exerted most strongly on transgenes that do not contain strong promoters, enhancers or other modulating sequences. Here we have systematically explored position effects using a transgene with the weak herpes-simplex-virus thymidine-kinase promoter, linked to the readily visualized lacZ indicator gene (HSV-TK-lacZ). Each transgenic fetus with detectable expression displayed a unique lacZ staining pattern. Thus expression of this construct is apparently dictated entirely by its chromosomal position, without any construct specificity. Furthermore the transgene is faithfully transmitted to subsequent generations, allowing for systematic mapping of changes in expression during development and in adult life. These results demonstrate that transgenes can indeed be powerful tools to probe the genome for active chromosomal regions, with the potential for identifying endogenous genes involved in organogenesis and pattern formation.
胚胎发育需要一个明确的基因表达时空程序，这可能会受到活跃染色体结构域的影响。这些染色体结构域可以通过整合到整个基因组中的转基因来检测，因为它们的表达会受到染色体位置的影响。位置效应可能对那些不包含强启动子、增强子或其他调控序列的转基因影响最为强烈。在这里，我们使用一个与易于观察的lacZ报告基因相连的弱单纯疱疹病毒胸苷激酶启动子的转基因（HSV-TK-lacZ），系统地研究了位置效应。每个有可检测表达的转基因胎儿都显示出独特的lacZ染色模式。因此，该构建体的表达显然完全由其染色体位置决定，而没有任何构建体特异性。此外，转基因能够忠实地传递给后代，从而可以系统地绘制发育过程中和成年期表达变化的图谱。这些结果表明，转基因确实可以成为探测基因组中活跃染色体区域的有力工具，具有识别参与器官发生和模式形成的内源基因的潜力。
