Schwyter D H, Huang J D, Dubnicoff T, Courey A J
Department of Chemistry and Biochemistry, University of California, Los Angeles 90095-1569, USA.
Mol Cell Biol. 1995 Jul;15(7):3960-8. doi: 10.1128/MCB.15.7.3960.
The Drosophila melanogaster decapentaplegic (dpp) gene encodes a transforming growth factor beta-related cell signaling molecule that plays a critical role in dorsal/ventral pattern formation. The dpp expression pattern in the Drosophila embryo is dynamic, consisting of three phases. Phase I, in which dpp is expressed in a broad dorsal domain, depends on elements in the dpp second intron that interact with the Dorsal transcription factor to repress transcription ventrally. In contrast, phases II and III, in which dpp is expressed first in broad longitudinal stripes (phase II) and subsequently in narrow longitudinal stripes (phase III), depend on multiple independent elements in the dpp 5'-flanking region. Several aspects of the normal dpp expression pattern appear to depend on the unique properties of the dpp core promoter. For example, this core promoter (extending from -22 to +6) is able to direct a phase II expression pattern in the absence of additional upstream or downstream regulatory elements. In addition, a ventral-specific enhancer in the dpp 5'-flanking region that binds the Dorsal factor activates the heterologous hsp70 core promoter but not the dpp core promoter. Thus, the dpp core promoter region may contribute to spatially regulated transcription both by interacting directly with spatially restricted activators and by modifying the activity of proteins bound to enhancer elements.
黑腹果蝇的“十五体瘫”（dpp）基因编码一种与转化生长因子β相关的细胞信号分子，该分子在背腹模式形成中起关键作用。果蝇胚胎中的dpp表达模式是动态的，包括三个阶段。第一阶段，dpp在广泛的背侧区域表达，这依赖于dpp第二个内含子中的元件，这些元件与背侧转录因子相互作用以抑制腹侧的转录。相反，第二阶段和第三阶段，dpp首先在广泛的纵向条纹中表达（第二阶段），随后在狭窄的纵向条纹中表达（第三阶段），这依赖于dpp 5'侧翼区域中的多个独立元件。正常dpp表达模式的几个方面似乎依赖于dpp核心启动子的独特特性。例如，这个核心启动子（从-22延伸到+6）在没有额外的上游或下游调控元件的情况下能够指导第二阶段的表达模式。此外，dpp 5'侧翼区域中与背侧因子结合的腹侧特异性增强子激活异源hsp70核心启动子，但不激活dpp核心启动子。因此，dpp核心启动子区域可能通过直接与空间受限的激活剂相互作用以及通过改变与增强子元件结合的蛋白质的活性来促进空间调控的转录。
