Castelli-Gair J, Müller J, Bienz M
Zoological Institute, University of Zürich, Switzerland.
Development. 1992 Apr;114(4):877-86. doi: 10.1242/dev.114.4.877.
An Ultrabithorax (Ubx) minigene constructed from three key Ubx control regions is capable of supporting development of Ubx null mutants throughout larval life and beyond to pharate flies, thereby rescuing the larval lethality due to the homeotic mutation. The cuticle of these flies shows that the minigene provides at least partial Ubx function in each of the four compartments whose morphogenetic pathways are determined by Ubx. We analyse beta-galactosidase patterns in imaginal discs conferred by each individual Ubx control region. From the comparison of these patterns with Ubx expression in Cbx mutants, we infer that long-range repressor elements in the chromosomal Ubx gene play an important role in the generation of Ubx expression patterns in imaginal discs. Expression and function of our Ubx minigenes indicate that Ubx control regions are capable of functioning properly out of context and detached from their normal chromosomal location within the homeotic gene complex.
由三个关键的超双胸（Ubx）调控区构建的Ubx微型基因能够支持Ubx基因缺失突变体在整个幼虫期直至蛹期果蝇的发育，从而挽救由于同源异型突变导致的幼虫致死性。这些果蝇的表皮表明，该微型基因在由Ubx决定形态发生途径的四个体节中的每一个都提供了至少部分Ubx功能。我们分析了由每个单独的Ubx调控区赋予的成虫盘β-半乳糖苷酶模式。通过将这些模式与Cbx突变体中Ubx的表达进行比较，我们推断染色体Ubx基因中的远距离抑制元件在成虫盘中Ubx表达模式的产生中起重要作用。我们的Ubx微型基因的表达和功能表明，Ubx调控区能够在脱离同源异型基因复合体中正常染色体位置的情况下正常发挥功能。
