GReD INSERM UMR1103, CNRS UMR6293, University of Clermont-Ferrand, Clermont-Ferrand, France.
Curr Top Dev Biol. 2012;98:277-301. doi: 10.1016/B978-0-12-386499-4.00011-2.
Understanding gene regulatory pathways underlying diversification of cell types during development is one of the major challenges in developmental biology. Progressive specification of mesodermal lineages that are at the origin of body wall muscles in Drosophila embryos has been extensively studied during past years, providing an attractive framework for dissecting cell type diversification processes. In particular, it has been found that muscle founder cells that are at the origin of individual muscles display specific expression of transcription factors that control diversification of muscle types. These factors, encoded by genes collectively called muscle identity genes, are activated in discrete subsets of muscle founders. As a result, each founder cell is thought to carry a unique combinatorial code of identity gene expression. Considering this, to define temporally and spatially restricted expression of identity genes, a set of coordinated upstream regulatory inputs is required. But also, to realize the identity program and to form specific muscle types with distinct properties, an efficient battery of downstream identity gene targets needs to be activated. Here we review how the specificity of expression and action of muscle identity genes is acquired.
理解发育过程中细胞类型多样化的基因调控途径是发育生物学的主要挑战之一。近年来，对果蝇胚胎中体壁肌肉起源的中胚层谱系的逐步特化进行了广泛研究，为剖析细胞类型多样化过程提供了一个有吸引力的框架。特别是，人们发现，作为个体肌肉起源的肌肉创始细胞特异性表达控制肌肉类型多样化的转录因子。这些因子由统称肌肉身份基因的基因编码，在离散的肌肉创始细胞亚群中被激活。因此，每个创始细胞被认为携带独特的身份基因表达组合代码。考虑到这一点，为了定义身份基因的时空限制表达，需要一组协调的上游调节输入。但是，为了实现身份程序并形成具有独特特性的特定肌肉类型，还需要激活有效的下游身份基因靶标。在这里，我们回顾了肌肉身份基因的表达和作用的特异性是如何获得的。
