Programming gene expression in developing epidermis.
Programming gene expression in developing epidermis.
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发表时间：
1994-09
期刊：
影响因子：
4.6
通讯作者：
Carolyn Byrne;Michael Tainsky;Elaine Fuchs
中科院分区：
文献类型：
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作者：
Carolyn Byrne;Michael Tainsky;Elaine Fuchs
角蛋白作为成体角质形成细胞的主要蛋白质，为研究小鼠表皮胚胎发生提供了重要的生化标志。在这里，我们使用了一种改进的方法，全安装原位杂交跟踪皮肤特异性表达的内源性角蛋白mRNA在整个胚胎发生。为了监测转录调控，我们将其与人表皮角蛋白启动子驱动的转基因的β-半乳糖苷酶表达相结合。这些研究从根本上改变了我们对表皮发育过程中基因表达程序如何建立的看法。具体地说，我们发现（1）基底角蛋白（K5和K14）基因首先在E9.5以高度区域性的方式被检测到，并且令人惊讶地早在单层外胚层阶段;（2）早期模式与形态发生本身无关，而是与底层间充质的胚胎起源的区域性差异有关，支持早期诱导线索是间充质的形态发生标准;（3）表皮角蛋白基因在周皮中表达，支持该层来自外胚层分层的观点，（4）K5和K14基因在胚胎后期的表达模式与增殖能力相平行，而不是分层;（5）K1和K10 mRNA最早在E13.5被检测到，其表达模式与分化有关，而与分层无关。表皮基因表达的这些模式使我们探索这些基因的潜在转录调节因子是否表达相似。我们发现，AP 2（而不是Sp1）cRNAs杂交的模式类似，但之前的基础角蛋白cRNAs。最后，使用培养细胞中的基因表达，我们证明了AP 2在通常不具有AP 2活性的细胞环境中对基底角蛋白表达具有强烈的诱导作用。
As the major proteins of adult keratinocytes, keratins provide biochemical markers for exploring mouse epidermal embryogenesis. Here, we used a modified method of whole-mount in situ hybridization to track skin-specific expression of endogenous keratin mRNAs throughout embryogenesis. To monitor transcriptional regulation, we coupled this with beta-galactosidase expression of a human epidermal keratin promoter-driven transgene. These studies have radically changed our perception of how the program of gene expression becomes established during epidermal development. Specifically, we have discovered that (1) basal keratin (K5 and K14) genes are first detected at E9.5 in a highly regional fashion, and surprisingly as early as the single layered ectodermal stage; (2) the early patterns do not correlate with morphogenesis per se, but rather with regional variations in the embryonic origin of underlying mesenchyme, supporting morphogenetic criteria that early inductive cues are mesenchymal; (3) epidermal keratin genes are expressed in periderm, supporting the notion that this layer arises from ectodermal stratification, even though it is simple epithelial-like in morphology and is subsequently sloughed during development; (4) later embryonic patterns of K5 and K14 gene expression parallel proliferative capacity and not stratification; and (5) K1 and K10 mRNAs are first detected as early as E13.5, and their patterns correlate with differentiation and not stratification. These patterns of epidermal gene expression led us to explore whether potential transcriptional regulators of these genes are expressed similarly. We show that AP2 (but not Sp1) cRNAs hybridize in a pattern similar to, but preceding that of basal keratin cRNAs. Finally, using gene expression in cultured cells, we demonstrate that AP2 has a strong inductive effect on basal keratin expression in a cellular environment that does not normally possess AP2 activity.