Differential expression of Broad-Complex transcription factors may forecast tissue-specific developmental fates during Drosophila metamorphosis.
Differential expression of Broad-Complex transcription factors may forecast tissue-specific developmental fates during Drosophila metamorphosis.
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发表时间：
1994-11
期刊：
影响因子：
4.6
通讯作者：
Ivette F. Emery;Vahe Bedian;Gregory M. Guild
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文献类型：
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作者：
Ivette F. Emery;Vahe Bedian;Gregory M. Guild
类固醇激素蜕皮激素通过激活包括初级反应转录调节因子和次级反应结构基因在内的一系列基因活性来启动果蝇的变态。广泛复合体（BR-C）的主要反应基因是由几个不同的遗传功能，并编码一个家庭的相关转录因子亚型。我们的目的是确定BR-C亚型是否是所有组织中主要蜕皮激素反应的组成部分，以及组织特异性亚型表达是否与组织特异性变态结局相关。我们使用特异性抗体试剂，识别和区分Z1，Z2和Z3 BR-C蛋白亚型，研究在变态的初始阶段的蛋白质表达模式。蛋白质印迹分析表明，BR-C异构体诱导在变态的开始，每一个独特的动力学的诱导和镇压。整体免疫染色显示，BR-C蛋白在所有幼虫和成虫组织的细胞核中积累，这表明BR-C在许多组织中被诱导为初级反应。几种组织表达不同水平和组合的BR-C亚型，这表明BR-C在确定许多平行蜕皮激素反应级联的组织特异性结果中是重要的。例如，蛹前唾液腺（在变态过程中用于组织溶解）表达Z1亚型，而成虫盘（用于细胞分化和形态发生）从Z2亚型的合成转变为Z1亚型的合成。蛹前中枢神经系统（用于组织重塑）表达所有亚型，其中Z3占主导地位。唾液腺染色体免疫染色表明，BR-C蛋白直接与多线基因组中的许多位点相互作用。最后，蛋白质印迹分析表明，不同的BR-C遗传功能可以与单一和特定的BR-C蛋白亚型。
The steroid hormone ecdysone initiates metamorphosis in Drosophila melanogaster by activating a cascade of gene activity that includes primary response transcriptional regulators and secondary response structural genes. The Broad-Complex (BR-C) primary response gene is composed of several distinct genetic functions and encodes a family of related transcription factor isoforms. Our objective was to determine whether BR-C isoforms were components of the primary ecdysone response in all tissues and whether tissue-specific isoform expression is associated with tissue-specific metamorphic outcomes. We used specific antibody reagents that recognize and distinguish among the Z1, Z2 and Z3 BR-C protein isoforms to study protein expression patterns during the initial stages of metamorphosis. Western blot analyses demonstrated that BR-C isoforms are induced at the onset of metamorphosis, each with unique kinetics of induction and repression. Whole-mount immunostaining showed that the BR-C proteins accumulate in the nuclei of all larval and imaginal tissues indicating that the BR-C is induced as a primary response in many tissues. Several tissues express different levels and combinations of the BR-C isoforms suggesting that the BR-C is important in determining the tissue-specific outcome of many parallel ecdysone response cascades. For example, prepupal salivary glands (destined for histolysis during metamorphosis) express Z1 isoforms while imaginal discs (destined for cell differentiation and morphogenesis) shift from the synthesis of Z2 isoforms to the synthesis of Z1 isoforms. The prepupal central nervous system (destined for tissue remodeling) expresses all isoforms, with Z3 predominating. Salivary gland chromosome immunostaining indicated that BR-C proteins interact directly with numerous loci in the polytene genome. Finally, western blot analyses showed that distinct BR-C genetic functions can be correlated with single and specific BR-C protein isoforms.